all: Compile globally without _GNU_SOURCE, define _BSD_SOURCE or _GNU_SOURCE where needed

src/Makefile

@@ -9,7 +9,7 @@ CC = gcc
 CROSS_CC = $(CROSS_COMPILE)$(CC)
 HOST_CC = $(HOST_COMPILE)$(CC)
 
-CPPFLAGS += -DVERSION=\"$(VERSION)\" -DBUILD_DATE="\"$(BUILD_DATE)\"" -D_GNU_SOURCE -D_POSIX_C_SOURCE=200809L
+CPPFLAGS += -DVERSION=\"$(VERSION)\" -DBUILD_DATE="\"$(BUILD_DATE)\"" -D_POSIX_C_SOURCE=200809L
 CFLAGS += -W -Wall -O2 -pedantic -std=c99
 LIBS += -lusb
 

src/cal.c

@@ -20,6 +20,12 @@
 
 /* This is simple CAL parser form Calvaria */
 
+#ifdef __linux__
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>

src/disk.c

@@ -16,6 +16,12 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef __linux__
+#ifndef _BSD_SOURCE
+#define _BSD_SOURCE
+#endif
+#endif
+
 #include <fcntl.h>
 #include <libgen.h>
 #include <unistd.h>

src/libusb-sniff.c

@@ -21,7 +21,11 @@
 /* usage: sudo USBSNIFF_WAIT=1 LD_PRELOAD=./libusb-sniff.so flasher-3.5 ... */
 /* usage: sudo USBSNIFF_SKIP_READ=1 USBSNIFF_SKIP_WRITE=1 LD_PRELOAD=./libusb-sniff.so flasher-3.5 ... */
 
+/* Enable RTLD_NEXT for glibc */
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>