cmake: improve configuration with templates

 - move cmake configuration from mxe-conf to cmake-conf
 - replace `echo` with templates for readability and maintenance
 - allow packages to set other dep files
 - set CMAKE_POLICY_DEFAULT_CMPNNNN in wrapper since
   `cmake_minimum_required` or `cmake_policy` can't be set in
   toolchain (closes #971)

5 files changed, 151 insertions, 65 deletions

diff --git a/Makefile b/Makefile
index 1364ebd..0e8d56a 100644
--- a/Makefile
+++ b/Makefile
@@ -61,7 +61,7 @@ STRIP_EXE       := $(true)
 # All pkgs have (implied) order-only dependencies on MXE_CONF_PKGS.
 # These aren't meaningful to the pkg list in http://mxe.cc/#packages so
 # use a list in case we want to separate autotools, cmake etc.
-MXE_CONF_PKGS := mxe-conf
+MXE_CONF_PKGS := cmake-conf mxe-conf
 
 # define some whitespace variables
 define newline
@@ -525,6 +525,7 @@ $(1): $(PREFIX)/$(3)/installed/$(1)
 $(PREFIX)/$(3)/installed/$(1): $(PKG_MAKEFILES) \
                           $(PKG_PATCHES) \
                           $(PKG_TESTFILES) \
+                          $($(1)_FILE_DEPS) \
                           $(addprefix $(PREFIX)/$(3)/installed/,$(value $(call LOOKUP_PKG_RULE,$(1),DEPS,$(3)))) \
                           $(and $($(3)_DEPS),$(addprefix $(PREFIX)/$($(3)_DEPS)/installed/,$(filter-out $(MXE_CONF_PKGS),$($($(3)_DEPS)_PKGS)))) \
                           | $(if $(DONT_CHECK_REQUIREMENTS),,check-requirements) \
diff --git a/src/cmake-conf.mk b/src/cmake-conf.mk
new file mode 100644
index 0000000..d9c086d
--- /dev/null
+++ b/src/cmake-conf.mk
@@ -0,0 +1,57 @@
+# This file is part of MXE. See LICENSE.md for licensing information.
+
+PKG            := cmake-conf
+$(PKG)_VERSION := 1
+$(PKG)_UPDATE  := echo 1
+$(PKG)_TARGETS := $(BUILD) $(MXE_TARGETS)
+$(PKG)_FILE_DEPS := $(wildcard $(PWD)/src/cmake/conf/*)
+
+define $(PKG)_BUILD
+    # create the CMake toolchain file using template
+    # individual packages (e.g. hdf5) should add their
+    # own files under CMAKE_TOOLCHAIN_DIR
+
+    mkdir -p '$(CMAKE_TOOLCHAIN_DIR)'
+    touch '$(CMAKE_TOOLCHAIN_DIR)/.gitkeep'
+    cmake-configure-file \
+        -DCMAKE_VERSION=$(cmake_VERSION) \
+        -DCMAKE_SHARED_BOOL=$(CMAKE_SHARED_BOOL) \
+        -DCMAKE_STATIC_BOOL=$(CMAKE_STATIC_BOOL) \
+        -DLIBTYPE=$(if $(BUILD_SHARED),SHARED,STATIC) \
+        -DPREFIX=$(PREFIX) \
+        -DTARGET=$(TARGET) \
+        -DBUILD=$(BUILD) \
+        -DCMAKE_TOOLCHAIN_DIR='$(CMAKE_TOOLCHAIN_DIR)' \
+        -DINPUT='$(PWD)/src/cmake/conf/mxe-conf.cmake.in' \
+        -DOUTPUT='$(CMAKE_TOOLCHAIN_FILE)'
+
+    #create prefixed cmake wrapper script
+    cmake-configure-file \
+        -DCMAKE_VERSION=$(cmake_VERSION) \
+        -DPREFIX=$(PREFIX) \
+        -DTARGET=$(TARGET) \
+        -DBUILD=$(BUILD) \
+        -DCMAKE_TOOLCHAIN_FILE='$(CMAKE_TOOLCHAIN_FILE)' \
+        -DCMAKE_RUNRESULT_FILE='$(CMAKE_RUNRESULT_FILE)' \
+        -DINPUT='$(PWD)/src/cmake/conf/target-cmake.in' \
+        -DOUTPUT='$(PREFIX)/bin/$(TARGET)-cmake'
+    chmod 0755 '$(PREFIX)/bin/$(TARGET)-cmake'
+endef
+
+define $(PKG)_BUILD_$(BUILD)
+    # install cmake modules
+    mkdir -p '$(PREFIX)/share/cmake/modules'
+    $(INSTALL) -m644 '$(PWD)/src/cmake/modules/'* '$(PREFIX)/share/cmake/modules'
+
+    # install cmake-configure-file for general use
+    # cmake-configure-file -DINPUT -DOUTPUT -DFOO -DBAR -D...
+    mkdir -p '$(PREFIX)/bin'
+    echo 'configure_file($${INPUT} $${OUTPUT} @ONLY)' \
+        > '$(PREFIX)/share/cmake/modules/configure_file.cmake'
+    (echo '#!/usr/bin/env bash'; \
+     echo 'exec "$(PREFIX)/$(BUILD)/bin/cmake" "$$@" \
+                    -P "$(PREFIX)/share/cmake/modules/configure_file.cmake"'; \
+    ) \
+             > '$(PREFIX)/bin/cmake-configure-file'
+    chmod 0755 '$(PREFIX)/bin/cmake-configure-file'
+endef
diff --git a/src/cmake/conf/mxe-conf.cmake.in b/src/cmake/conf/mxe-conf.cmake.in
new file mode 100644
index 0000000..d9c6a44
--- /dev/null
+++ b/src/cmake/conf/mxe-conf.cmake.in
@@ -0,0 +1,67 @@
+# This file is part of MXE. See LICENSE.md for licensing information.
+
+# https://cmake.org/cmake/help/latest
+
+# Can't set `cmake_minimum_required` or `cmake_policy` in toolchain
+# since toolchain is read before CMakeLists.txt
+# See `target-cmake.in` for CMAKE_POLICY_DEFAULT_CMPNNNN
+
+# Check if we are using mxe supplied version
+#   - toolchain is included multiple times so set a guard in
+#     environment to suppress duplicate messages
+if(NOT ${CMAKE_COMMAND} STREQUAL @PREFIX@/@BUILD@/bin/cmake AND NOT DEFINED ENV{_MXE_CMAKE_TOOLCHAIN_INCLUDED})
+    message(WARNING "
+** Warning: direct use of toolchain file is deprecated
+** Please use prefixed wrapper script instead:
+     @TARGET@-cmake [options] <path-to-source>
+       - uses mxe supplied cmake version @CMAKE_VERSION@
+       - loads toolchain
+       - loads common run results
+       - sets various policy defaults
+    ")
+    set(ENV{_MXE_CMAKE_TOOLCHAIN_INCLUDED} TRUE)
+endif()
+
+## General configuration
+set(CMAKE_SYSTEM_NAME Windows)
+set(MSYS 1)
+set(CMAKE_BUILD_TYPE Release CACHE STRING "Debug|Release|RelWithDebInfo|MinSizeRel" FORCE)
+set(CMAKE_EXPORT_NO_PACKAGE_REGISTRY ON)
+# Workaround for https://www.cmake.org/Bug/view.php?id=14075
+set(CMAKE_CROSS_COMPILING ON)
+
+
+## Library config
+set(BUILD_SHARED_LIBS @CMAKE_SHARED_BOOL@ CACHE BOOL "BUILD_SHARED_LIBS" FORCE)
+set(BUILD_STATIC_LIBS @CMAKE_STATIC_BOOL@ CACHE BOOL "BUILD_STATIC_LIBS" FORCE)
+set(BUILD_SHARED @CMAKE_SHARED_BOOL@ CACHE BOOL "BUILD_SHARED" FORCE)
+set(BUILD_STATIC @CMAKE_STATIC_BOOL@ CACHE BOOL "BUILD_STATIC" FORCE)
+set(LIBTYPE @LIBTYPE@)
+
+
+## Paths etc.
+set(CMAKE_FIND_ROOT_PATH @PREFIX@/@TARGET@)
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_PREFIX_PATH @PREFIX@/@TARGET@)
+set(CMAKE_INSTALL_PREFIX @PREFIX@/@TARGET@ CACHE PATH "Installation Prefix")
+# For custom mxe FindPackage scripts
+set(CMAKE_MODULE_PATH "@PREFIX@/share/cmake/modules" ${CMAKE_MODULE_PATH})
+
+
+## Programs
+set(CMAKE_C_COMPILER @PREFIX@/bin/@TARGET@-gcc)
+set(CMAKE_CXX_COMPILER @PREFIX@/bin/@TARGET@-g++)
+set(CMAKE_Fortran_COMPILER @PREFIX@/bin/@TARGET@-gfortran)
+set(CMAKE_RC_COMPILER @PREFIX@/bin/@TARGET@-windres)
+# CMAKE_RC_COMPILE_OBJECT is defined in:
+#     <cmake root>/share/cmake-X.Y/Modules/Platform/Windows-windres.cmake
+
+## Individual package configuration
+file(GLOB mxe_cmake_files
+    "@CMAKE_TOOLCHAIN_DIR@/*.cmake"
+)
+foreach(mxe_cmake_file ${mxe_cmake_files})
+    include(${mxe_cmake_file})
+endforeach()
diff --git a/src/cmake/conf/target-cmake.in b/src/cmake/conf/target-cmake.in
new file mode 100644
index 0000000..5858a7b
--- /dev/null
+++ b/src/cmake/conf/target-cmake.in
@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+echo "== Using MXE wrapper: @PREFIX@/bin/@TARGET@-cmake"
+
+# https://cmake.org/cmake/help/latest/manual/cmake-policies.7.html
+# https://cmake.org/cmake/help/latest/variable/CMAKE_POLICY_DEFAULT_CMPNNNN.html
+POLICIES=(0017,0020)
+
+unset NO_MXE_TOOLCHAIN
+if echo -- "$@" | grep -Ewq "(--build|-E|--system-information)" ; then
+    NO_MXE_TOOLCHAIN=1
+fi
+if [[ "$NO_MXE_TOOLCHAIN" == "1" ]]; then
+    echo "== Skip using MXE toolchain: @CMAKE_TOOLCHAIN_FILE@"
+    # see https://github.com/mxe/mxe/issues/932
+    exec "@PREFIX@/@BUILD@/bin/cmake" "$@"
+else
+    echo "     - cmake version @CMAKE_VERSION@"
+    echo "     - warnings for unused CMAKE_POLICY_DEFAULT variables can be ignored"
+    echo "== Using MXE toolchain: @CMAKE_TOOLCHAIN_FILE@"
+    echo "== Using MXE runresult: @CMAKE_RUNRESULT_FILE@"
+    exec "@PREFIX@/@BUILD@/bin/cmake" \
+              -DCMAKE_TOOLCHAIN_FILE="@CMAKE_TOOLCHAIN_FILE@" \
+              `eval echo -DCMAKE_POLICY_DEFAULT_CMP{$POLICIES}=NEW` \
+              -C"@CMAKE_RUNRESULT_FILE@" "$@"
+fi
diff --git a/src/mxe-conf.mk b/src/mxe-conf.mk
index a95a1ed..ef67b47 100644
--- a/src/mxe-conf.mk
+++ b/src/mxe-conf.mk
@@ -16,66 +16,6 @@ define $(PKG)_BUILD
     # setting ac_cv_build bypasses the config.guess check in every package
     echo "ac_cv_build=$(BUILD)" > '$(PREFIX)/$(TARGET)/share/config.site'
 
-    # create the CMake toolchain file
-    # individual packages (e.g. hdf5) should add their
-    # own files under CMAKE_TOOLCHAIN_DIR
-    # CMAKE_RC_COMPILE_OBJECT is defined in:
-    #     <cmake root>/share/cmake-X.Y/Modules/Platform/Windows-windres.cmake
-
-    mkdir -p '$(CMAKE_TOOLCHAIN_DIR)'
-    touch '$(CMAKE_TOOLCHAIN_DIR)/.gitkeep'
-    (echo 'set(CMAKE_SYSTEM_NAME Windows)'; \
-     echo 'set(MSYS 1)'; \
-     echo 'set(BUILD_SHARED_LIBS $(CMAKE_SHARED_BOOL) CACHE BOOL "BUILD_SHARED_LIBS" FORCE)'; \
-     echo 'set(BUILD_STATIC_LIBS $(CMAKE_STATIC_BOOL) CACHE BOOL "BUILD_STATIC_LIBS" FORCE)'; \
-     echo 'set(BUILD_SHARED $(CMAKE_SHARED_BOOL) CACHE BOOL "BUILD_SHARED" FORCE)'; \
-     echo 'set(BUILD_STATIC $(CMAKE_STATIC_BOOL) CACHE BOOL "BUILD_STATIC" FORCE)'; \
-     echo 'set(LIBTYPE $(if $(BUILD_SHARED),SHARED,STATIC))'; \
-     echo 'set(CMAKE_EXPORT_NO_PACKAGE_REGISTRY ON)'; \
-     echo 'set(CMAKE_PREFIX_PATH $(PREFIX)/$(TARGET))'; \
-     echo 'set(CMAKE_FIND_ROOT_PATH $(PREFIX)/$(TARGET))'; \
-     echo 'set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)'; \
-     echo 'set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)'; \
-     echo 'set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)'; \
-     echo 'set(CMAKE_C_COMPILER $(PREFIX)/bin/$(TARGET)-gcc)'; \
-     echo 'set(CMAKE_CXX_COMPILER $(PREFIX)/bin/$(TARGET)-g++)'; \
-     echo 'set(CMAKE_Fortran_COMPILER $(PREFIX)/bin/$(TARGET)-gfortran)'; \
-     echo 'set(CMAKE_RC_COMPILER $(PREFIX)/bin/$(TARGET)-windres)'; \
-     echo 'set(CMAKE_MODULE_PATH "$(PREFIX)/share/cmake/modules" $${CMAKE_MODULE_PATH}) # For mxe FindPackage scripts'; \
-     echo 'set(CMAKE_INSTALL_PREFIX $(PREFIX)/$(TARGET) CACHE PATH "Installation Prefix")'; \
-     echo 'set(CMAKE_BUILD_TYPE Release CACHE STRING "Debug|Release|RelWithDebInfo|MinSizeRel" FORCE)'; \
-     echo 'set(CMAKE_CROSS_COMPILING ON) # Workaround for https://www.cmake.org/Bug/view.php?id=14075'; \
-     echo ''; \
-     echo 'file(GLOB mxe_cmake_files'; \
-     echo '    "$(CMAKE_TOOLCHAIN_DIR)/*.cmake"'; \
-     echo ')'; \
-     echo 'foreach(mxe_cmake_file $${mxe_cmake_files})'; \
-     echo '    include($${mxe_cmake_file})'; \
-     echo 'endforeach()'; \
-     ) > '$(CMAKE_TOOLCHAIN_FILE)'
-
-    #create prefixed cmake wrapper script
-    (echo '#!/usr/bin/env bash'; \
-     echo 'echo "== Using MXE wrapper: $(PREFIX)/bin/$(TARGET)-cmake"'; \
-     echo 'unset NO_MXE_TOOLCHAIN'; \
-     echo 'if echo -- "$$@" | grep -Ewq "(--build|-E|--system-information)" ; then'; \
-     echo '    NO_MXE_TOOLCHAIN=1'; \
-     echo 'fi'; \
-     echo 'if [[ "$$NO_MXE_TOOLCHAIN" == "1" ]]; then'; \
-     echo '    echo "== Skip using MXE toolchain: $(CMAKE_TOOLCHAIN_FILE)"'; \
-     echo '    # see https://github.com/mxe/mxe/issues/932'; \
-     echo '    exec "$(PREFIX)/$(BUILD)/bin/cmake" "$$@"'; \
-     echo 'else'; \
-     echo '    echo "== Using MXE toolchain: $(CMAKE_TOOLCHAIN_FILE)"'; \
-     echo '    echo "== Using MXE runresult: $(CMAKE_RUNRESULT_FILE)"'; \
-     echo '    exec "$(PREFIX)/$(BUILD)/bin/cmake" \
-                         -DCMAKE_TOOLCHAIN_FILE="$(CMAKE_TOOLCHAIN_FILE)" \
-                         -C"$(CMAKE_RUNRESULT_FILE)" "$$@"'; \
-     echo 'fi'; \
-    ) \
-             > '$(PREFIX)/bin/$(TARGET)-cmake'
-    chmod 0755 '$(PREFIX)/bin/$(TARGET)-cmake'
-
     # create pkg-config files for OpenGL/GLU
     mkdir -p '$(PREFIX)/$(TARGET)/lib/pkgconfig'
     (echo 'Name: gl'; \
@@ -96,10 +36,6 @@ define $(PKG)_BUILD_$(BUILD)
     mkdir -p '$(PREFIX)/bin'
     $(INSTALL) -m755 '$(EXT_DIR)/config.guess' '$(PREFIX)/bin/'
 
-    # install cmake modules
-    mkdir -p '$(PREFIX)/share/cmake/modules'
-    $(INSTALL) -m644 '$(PWD)/src/cmake/modules/'* '$(PREFIX)/share/cmake/modules'
-
     # fail early if autotools can't autoreconf
     # 1. detect mismatches in installation locations
     # 2. ???