diff --git a/Makefile b/Makefile
index 303a527..5be80cd 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ endif
 
 CFLAGS		+= -Wall
 
-ifneq ($(findstring darwin,$(OSTYPE)),)
+ifneq ($(findstring Darwin,$(OSTYPE)),)
 CFLAGS+=-D__APPLE__
 else
 CFLAGS		+= -static
diff --git a/lpc21isp.c b/lpc21isp.c
index ad1cdcb..98f5500 100644
--- a/lpc21isp.c
+++ b/lpc21isp.c
@@ -1212,7 +1212,9 @@ void ReceiveComPort(ISP_ENVIRONMENT *IspEnvironment,
 {
     unsigned long tmp_realsize;
     unsigned long nr_of_0x0A = 0;
+#pragma GCC diagnostic ignored "-Wunused-but-set-variable"
     unsigned long nr_of_0x0D = 0;
+#pragma GCC diagnostic warning "-Wunused-but-set-variable"
     int eof = 0;
     unsigned long p;
     unsigned char *Answer;