fix compiler detection in makefile

Reducibility_Multiplex/Makefile

@@ -1,12 +1,30 @@
 CC=gcc
-CFLAGS=-Iinclude -g -O3 
+CFLAGS=-O2 
+LDFLAGS=-lm -lgmp -lz
+
+IS_CC_GCC=$(shell $(CC) --version | grep -Eic 'gcc')
+IS_CC_CLANG=$(shell $(CC) --version | grep -Eic '(llvm|clang)')
+IS_CC_ICC=$(shell $(CC) --version | grep -Eic 'Intel')
+
+ifeq ($(IS_CC_GCC), 1)
+	CFLAGS+=-fopenmp
+else
+    ifneq ($(IS_CC_CGLANG), 0)
+	LDFLAGS+=-lomp
+    endif
+#else 
+#    ifeq ($(IS_CC_ICC), 1)
+#
+#    endif
+
+endif
 
 
 all: reducibility
 
 clean:
-	rm -f reducibility_complexity 
+	rm -f reducibility_complexity
 
 reducibility: reducibility_complexity.c
-	$(CC) $(CFLAGS) reducibility_complexity.c  -fopenmp -lm -lgmp -lz -o  reducibility_complexity
+	$(CC) $(CFLAGS) $(LDFLAGS)  reducibility_complexity.c  -o  reducibility_complexity