Teach find_(library|file|path) to get prefixes from PATH (#15370)

The find_package command already knows how to compute installation
prefixes from PATH.  Use the same approach to establish prefixes for
find_library, find_file, and find_path to use to look in directories
like "<prefix>/lib[/<arch>]" and "<prefix>/include" for libraries and
headers.  This will reduce the amount of configuration end users need to
do to establish a work environment rooted under a specific prefix.

3 files changed, 23 insertions, 2 deletions

diff --git a/Source/cmFindBase.cxx b/Source/cmFindBase.cxx
index 6e55533..4336e1c 100644
--- a/Source/cmFindBase.cxx
+++ b/Source/cmFindBase.cxx
@@ -275,6 +275,7 @@ void cmFindBase::FillSystemEnvironmentPath()
   if(!this->EnvironmentPath.empty())
     {
     paths.AddEnvPath(this->EnvironmentPath);
+    paths.AddEnvPrefixPath("PATH", true);
     }
   // Add PATH
   paths.AddEnvPath("PATH");
diff --git a/Source/cmSearchPath.cxx b/Source/cmSearchPath.cxx
index 861dbf1..1e777ab 100644
--- a/Source/cmSearchPath.cxx
+++ b/Source/cmSearchPath.cxx
@@ -136,10 +136,30 @@ void cmSearchPath::AddCMakePrefixPath(const std::string& variable)
 }
 
 //----------------------------------------------------------------------------
-void cmSearchPath::AddEnvPrefixPath(const std::string& variable)
+static std::string cmSearchPathStripBin(std::string const& s)
+{
+  // If the path is a PREFIX/bin case then add its parent instead.
+  if((cmHasLiteralSuffix(s, "/bin")) ||
+     (cmHasLiteralSuffix(s, "/sbin")))
+    {
+    return cmSystemTools::GetFilenamePath(s);
+    }
+  else
+    {
+    return s;
+    }
+}
+
+//----------------------------------------------------------------------------
+void cmSearchPath::AddEnvPrefixPath(const std::string& variable, bool stripBin)
 {
   std::vector<std::string> expanded;
   cmSystemTools::GetPath(expanded, variable.c_str());
+  if (stripBin)
+    {
+    std::transform(expanded.begin(), expanded.end(), expanded.begin(),
+                   cmSearchPathStripBin);
+    }
   this->AddPrefixPaths(expanded);
 }
 
diff --git a/Source/cmSearchPath.h b/Source/cmSearchPath.h
index 51a6149..41c680d 100644
--- a/Source/cmSearchPath.h
+++ b/Source/cmSearchPath.h
@@ -42,7 +42,7 @@ public:
   void AddCMakePath(const std::string& variable);
   void AddEnvPath(const std::string& variable);
   void AddCMakePrefixPath(const std::string& variable);
-  void AddEnvPrefixPath(const std::string& variable);
+  void AddEnvPrefixPath(const std::string& variable, bool stripBin = false);
   void AddSuffixes(const std::vector<std::string>& suffixes);
 
 protected: