diff --git a/CMakeLists.txt b/CMakeLists.txt
index d032aff..18e81ed 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@ endif()
 if(CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
   message("setting intel true")
   set(IntelComp true )
-elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU*")
+elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU*" OR CMAKE_CXX_COMPILER_ID MATCHES "Clang*")
   set(GNUComp true )
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "pgc*")
   set(PGIComp true )
@@ -28,13 +28,16 @@ if( (BUILD_RELEASE) OR (BUILD_PRODUCTION) )
     set(CMAKE_Fortran_4_FLAGS "-O3 -g " CACHE INTERNAL "" )
     set(CMAKE_C_FLAGS "-O3 -DLINUX " CACHE INTERNAL "" )
   elseif(GNUComp)
-    set(CMAKE_Fortran_d_FLAGS "-fno-range-check -O3 -ggdb -fdefault-real-8 -funroll-loops  " CACHE INTERNAL "" )
-    set(CMAKE_Fortran_8_FLAGS "-fno-range-check -O3  -ggdb -fdefault-integer-8 -fdefault-real-8 -funroll-loops  " CACHE INTERNAL "" )
-    set(CMAKE_Fortran_4_FLAGS "-fno-range-check -O3 -ggdb -funroll-loops  " CACHE INTERNAL "" )
-    set(CMAKE_C_FLAGS "-O3 -DLINUX " CACHE INTERNAL "" )
-  elseif(PGIComp)
+    set(CMAKE_Fortran_d_FLAGS "-fno-range-check -O3 -ggdb -fdefault-real-8 -funroll-loops " CACHE INTERNAL "" )
+    set(CMAKE_Fortran_8_FLAGS "-fno-range-check -O3 -ggdb -fdefault-integer-8 -fdefault-real-8 -funroll-loops " CACHE INTERNAL "" )
+    set(CMAKE_Fortran_4_FLAGS "-fno-range-check -O3 -ggdb -funroll-loops " CACHE INTERNAL "" )
+    if(APPLE)
+      set(CMAKE_C_FLAGS "-O3 -DAPPLE " CACHE INTERNAL "" )
+    elseif(UNIX)
+      set(CMAKE_C_FLAGS "-O3 -DLINUX " CACHE INTERNAL "" )
+    endif(UNIX)
   else()
-    message("unkown compiler!")
+    message("unknown compiler!")
     exit()
   endif()
 endif()
diff --git a/src/mova2i.c b/src/mova2i.c
index e96bac4..239c494 100644
--- a/src/mova2i.c
+++ b/src/mova2i.c
@@ -47,6 +47,9 @@ C$$$i*/
 #ifdef LINUX
    int mova2i_(unsigned char *a)
 #endif
+#ifdef APPLE
+   int mova2i_(unsigned char *a)
+#endif
 #ifdef LINUXF90
    int MOVA2I(unsigned char *a)
 #endif
diff --git a/src/summary.c b/src/summary.c
index 96bcccb..ea38425 100644
--- a/src/summary.c
+++ b/src/summary.c
@@ -449,7 +449,7 @@ void print_timing (string, time)
 void summary( returnVal  )
 int * returnVal;
 #endif
-#ifdef __linux__
+#if defined(LINUX) || (APPLE)
 void summary_ (int *returnVal)
 #endif
 {
@@ -475,7 +475,7 @@ void summary_ (int *returnVal)
 #ifdef _AIX
 void start()
 #endif
-#ifdef __linux__
+#if defined(LINUX) || defined(APPLE)
 void start_ ()
 #endif
 {