Fix TFEL Ticket #257

Author: thelfer

cmake/modules/compiler.cmake

@@ -117,12 +117,6 @@ MACRO(tfel_enable_cxx_compiler_flag out)
 ENDMACRO(tfel_enable_cxx_compiler_flag)
 
 #compiler specific options
-set(CMAKE_C_FLAGS           "")
-set(CMAKE_C_FLAGS_RELEASE "")
-set(CMAKE_C_FLAGS_DEBUG   "")
-set(CMAKE_CXX_FLAGS         "")
-set(CMAKE_CXX_FLAGS_RELEASE "")
-set(CMAKE_CXX_FLAGS_DEBUG   "")
 set(VISIBILITY_FLAGS   "")
 set(OPTIMISATION_FLAGS "")
 set(COMPILER_WARNINGS  "")
@@ -161,10 +155,13 @@ endif(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
 # `conda` adds `-I$PREFIX/include` in the `CFLAGS` and `CXXFLAGS`,
 # thus, using those variables `CFLAGS` and `CXXFLAGS` solves the issue and is more
 # consistent with other `conda` packages.
-if(USE_EXTERNAL_COMPILER_FLAGS)
-  set(CMAKE_C_FLAGS "$ENV{CFLAGS}")
-  set(CMAKE_CXX_FLAGS "${COMPILER_WARNINGS} $ENV{CXXFLAGS}")
-else(USE_EXTERNAL_COMPILER_FLAGS)
+if(NOT USE_EXTERNAL_COMPILER_FLAGS)
+  set(CMAKE_C_FLAGS           "")
+  set(CMAKE_C_FLAGS_RELEASE "")
+  set(CMAKE_C_FLAGS_DEBUG   "")
+  set(CMAKE_CXX_FLAGS         "")
+  set(CMAKE_CXX_FLAGS_RELEASE "")
+  set(CMAKE_CXX_FLAGS_DEBUG   "")
   set(CMAKE_C_FLAGS "${COMPILER_FLAGS} ${COMPILER_CFLAGS}")
   set(CMAKE_CXX_FLAGS "${VISIBILITY_FLAGS} ${COMPILER_WARNINGS} ${COMPILER_FLAGS} ${COMPILER_CXXFLAGS}")
   if(CMAKE_BUILD_TYPE STREQUAL "Profiling")
@@ -183,5 +180,5 @@ else(USE_EXTERNAL_COMPILER_FLAGS)
       set(CMAKE_CXX_FLAGS "${OPTIMISATION_FLAGS_MARCH} ${CMAKE_CXX_FLAGS}")
     endif(NOT enable-portable-build)
   endif(CMAKE_BUILD_TYPE STREQUAL "Profiling")
-endif(USE_EXTERNAL_COMPILER_FLAGS)
+endif(NOT USE_EXTERNAL_COMPILER_FLAGS)