build: remove StrawberryPerl from ENV{PATH}

On Windows, StrawberryPerl tools and libraries exposed in the PATH
environment variable can pollute and break the build, remove any such
entries for WIN32 as a startup cmake action.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

CMakeLists.txt

@@ -33,6 +33,10 @@ endif()
 
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
 
+if(WIN32)
+    include(RemoveStrawberryPerlFromPATH)
+endif()
+
 if(UPDATE_APPCAST)
     include(UpdateAppcast)
 endif()

cmake/RemoveStrawberryPerlFromPATH.cmake

@@ -0,0 +1,17 @@
+# Remove StrawberryPerl from the PATH environment variable due to various build
+# pollution.
+unset(new_path)
+
+message("BEFORE: $ENV{PATH}")
+
+foreach(p $ENV{PATH})
+    if(NOT p MATCHES "(^|\\\\)[Ss]trawberry\\\\([Pp]erl|[Cc])\\\\(.*\\\\)?[Bb]in$")
+        list(APPEND new_path ${p})
+    endif()
+endforeach(
+
+set(ENV{PATH} "${new_path}")
+
+message("AFTER: $ENV{PATH}")
+
+# vim:sw=4 et sts=4 ts=8: