find_*: Add support for REQUIRED keyword

In the same spirit as the REQUIRED keyword on find_package, this will
stop cmake execution with an error on a failed find_program, find_file,
find_path or find_library.

1 files changed, 7 insertions, 2 deletions

diff --git a/Help/command/FIND_XXX.txt b/Help/command/FIND_XXX.txt
index 42bf52b..cebe051 100644
--- a/Help/command/FIND_XXX.txt
+++ b/Help/command/FIND_XXX.txt
@@ -15,6 +15,7 @@ The general signature is:
              [PATHS path1 [path2 ... ENV var]]
              [PATH_SUFFIXES suffix1 [suffix2 ...]]
              [DOC "cache documentation string"]
+             [REQUIRED]
              [NO_DEFAULT_PATH]
              [NO_PACKAGE_ROOT_PATH]
              [NO_CMAKE_PATH]
@@ -31,8 +32,9 @@ A cache entry named by ``<VAR>`` is created to store the result
 of this command.
 If the |SEARCH_XXX| is found the result is stored in the variable
 and the search will not be repeated unless the variable is cleared.
-If nothing is found, the result will be
-``<VAR>-NOTFOUND``, and the search will be attempted again the
+If nothing is found, the result will be ``<VAR>-NOTFOUND``.
+The ``REQUIRED`` option stops processing with an error message if nothing
+is found, otherwise the search will be attempted again the
 next time |FIND_XXX| is invoked with the same variable.
 
 Options include:
@@ -57,6 +59,9 @@ Options include:
 ``DOC``
   Specify the documentation string for the ``<VAR>`` cache entry.
 
+``REQUIRED``
+  Stop processing with an error message if nothing is found.
+
 If ``NO_DEFAULT_PATH`` is specified, then no additional paths are
 added to the search.
 If ``NO_DEFAULT_PATH`` is not specified, the search process is as follows: