Add GRASS plugin CMake macro to find extra includes of GRASS compilation

Such includes may need found again when including some GRASS headers.

cmake/FindGRASS.cmake

@@ -4,6 +4,33 @@
 # Redistribution and use is allowed according to the terms of the BSD license.
 # For details see the accompanying COPYING-CMAKE-SCRIPTS file.
 
+# Macro that checks for extra include directories set during GRASS compilation.
+# This helps for platforms where GRASS is built against dependencies in
+# non-standard locations; like on Mac, where the system gettext is too old and
+# GRASS is built off of gettext in /usr/local/opt, or some other custom prefix.
+# Such includes may need found again when including some GRASS headers.
+
+MACRO (CHECK_GRASS_EXTRA_INCLUDE_DIRS GRASS_VERSION)
+  SET(GRASS_EXTRA_INCLUDE_DIRS${GRASS_VERSION} ""
+      CACHE STRING "Extra includes string used for GRASS${GRASS_VERSION}")
+
+  IF(UNIX AND EXISTS ${GRASS_INCLUDE_DIR${GRASS_VERSION}}/Make/Platform.make
+     AND "${GRASS${GRASS_VERSION}_EXTRA_INCLUDE_DIRS}" STREQUAL "")
+
+    FILE(READ ${GRASS_INCLUDE_DIR${GRASS_VERSION}}/Make/Platform.make _platformfile)
+    STRING(REGEX MATCH "INCLUDE_DIRS *= [^\n]*" _config_includes "${_platformfile}")
+    IF(NOT "${_config_includes}" STREQUAL "")
+      STRING(REGEX REPLACE "INCLUDE_DIRS *= *([^\n]*)" "\\1" _extra_includes "${_config_includes}")
+    ENDIF()
+    IF(NOT "${_extra_includes}" STREQUAL "")
+      SET(GRASS_EXTRA_INCLUDE_DIRS${GRASS_VERSION} ${_extra_includes}
+          CACHE STRING "Extra includes string used for GRASS${GRASS_VERSION}" FORCE)
+    ENDIF()
+  ENDIF()
+
+  MARK_AS_ADVANCED (GRASS_EXTRA_INCLUDE_DIRS${GRASS_VERSION})
+ENDMACRO (CHECK_GRASS_EXTRA_INCLUDE_DIRS GRASS_VERSION)
+
 # macro that checks for grass installation in specified directory
 
 MACRO (CHECK_GRASS G_PREFIX)
@@ -108,10 +135,12 @@ MACRO (CHECK_GRASS G_PREFIX)
           SET(GRASS_FOUND${GRASS_FIND_VERSION} TRUE)
           SET(GRASS_FOUND TRUE) # GRASS_FOUND is true if at least one version was found
           SET(GRASS_PREFIX${GRASS_CACHE_VERSION} ${G_PREFIX})
+          CHECK_GRASS_EXTRA_INCLUDE_DIRS(${GRASS_CACHE_VERSION})
           IF(GRASS_FIND_VERSION EQUAL 6)
             # Set also normal variable with number
             SET(GRASS_INCLUDE_DIR${GRASS_FIND_VERSION} ${GRASS_INCLUDE_DIR${GRASS_CACHE_VERSION}})
             SET(GRASS_PREFIX${GRASS_FIND_VERSION} ${G_PREFIX})
+            CHECK_GRASS_EXTRA_INCLUDE_DIRS(${GRASS_FIND_VERSION})
           ENDIF(GRASS_FIND_VERSION EQUAL 6)
         ENDIF(GRASS_LIBRARIES_FOUND${GRASS_FIND_VERSION})
     ENDIF(GRASS_MAJOR_VERSION${GRASS_FIND_VERSION} EQUAL GRASS_FIND_VERSION)

src/plugins/grass/CMakeLists.txt

@@ -190,7 +190,7 @@ MACRO(ADD_GRASSPLUGIN GRASS_BUILD_VERSION)
     )
 
     SET_TARGET_PROPERTIES(grassplugin${GRASS_BUILD_VERSION} PROPERTIES
-      COMPILE_FLAGS "-DGRASS_BASE=\\\"${GRASS_PREFIX}\\\""
+      COMPILE_FLAGS "-DGRASS_BASE=\\\"${GRASS_PREFIX}\\\" ${GRASS_EXTRA_INCLUDE_DIRS${GRASS_BUILD_VERSION}}"
     )
 
     IF(MSVC)
@@ -216,7 +216,7 @@ MACRO(ADD_GRASSPLUGIN GRASS_BUILD_VERSION)
     ADD_EXECUTABLE(qgis.g.browser${GRASS_BUILD_VERSION} ${GRASS_BROWSER_SRCS})
 
     SET_TARGET_PROPERTIES(qgis.g.browser${GRASS_BUILD_VERSION} PROPERTIES
-      COMPILE_FLAGS "-DGRASS_BASE=\\\"${GRASS_PREFIX}\\\""
+      COMPILE_FLAGS "-DGRASS_BASE=\\\"${GRASS_PREFIX}\\\" ${GRASS_EXTRA_INCLUDE_DIRS${GRASS_BUILD_VERSION}}"
     )
 
     TARGET_LINK_LIBRARIES (qgis.g.browser${GRASS_BUILD_VERSION}