Use add_compile_definitions for newer CMake versions.

add_definitions is deprecated.
Note the new command does not need the -D qualifier but will detect
if there is one and act accordingly. This helps with package
configuration files that have "-DVAR" in their COMPILE_DEFINTIONS

As some packages actually already add the -D qualifier we now detect
that to be able to support old CMake version without
add_compile_definitions. In this case we prevent adding another -D
and use add_definitions.

cmake/Modules/OpmCompile.cmake

@@ -29,7 +29,11 @@ macro (opm_compile opm)
 
   # create this library, if there are any compilation units
   link_directories (${${opm}_LIBRARY_DIRS})
-  add_definitions (${${opm}_DEFINITIONS})
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.12")
+    add_compile_definitions (${${opm}_DEFINITIONS})
+  else()
+    add_definitions(${${opm}_DEFINITIONS})
+  endif()
   set (${opm}_VERSION "${${opm}_VERSION_MAJOR}.${${opm}_VERSION_MINOR}")
   if (${opm}_SOURCES)
         add_library (${${opm}_TARGET} ${${opm}_LIBRARY_TYPE} ${${opm}_SOURCES})

cmake/Modules/OpmPackage.cmake

@@ -96,9 +96,13 @@ macro (find_opm_package module deps header lib defs prog conf)
   # compile with this option to avoid avalanche of warnings
   set (${module}_DEFINITIONS "${${module}_DEFINITIONS}")
   foreach (_def IN ITEMS ${defs})
-	list (APPEND ${module}_DEFINITIONS "-D${_def}")
+    if(_def MATCHES "^[A-Za-z].*")
+      list (APPEND ${module}_DEFINITIONS "-D${_def}")
+    endif()
   endforeach (_def)
 
+  list (APPEND ${module}_DEFINITIONS ${defs})
+
   # tidy the lists before returning them
   remove_dup_deps (${module})