--- libowfat-0.28/GNUmakefile
+++ libowfat-0.28-musl/GNUmakefile
@@ -24,6 +24,7 @@
 # CFLAGS += -fstrict-aliasing -Wstrict-aliasing=2
 
 CFLAGS += -D_REENTRANT
+CFLAGS += -D_GNU_SOURCE
 
 # startrip
 ifneq ($(DEBUG),)
--- libowfat-0.28/Makefile
+++ libowfat-0.28-musl/Makefile
@@ -24,7 +24,8 @@
 
 # CFLAGS += -fstrict-aliasing -Wstrict-aliasing=2
 
-CFLAGS += -D_REENTRANT
+CFLAGS += -D_REENTRANT 
+CFLAGS += -D_GNU_SOURCE
 
 array_allocate.o: array/array_allocate.c safemult.h uint16.h uint32.h \
   uint64.h array.h byte.h