diff --git a/Makefile.am b/Makefile.am
index 4aa3d846cc..02aac471f2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -15,7 +15,11 @@ SHARED_VERSION=2:49:1 # = *.so.1.1.49
 
 MKDIR=mkdir -p
 
-AM_CFLAGS = -Wno-endif-labels # Needed to prevent warnings in ieee80.c.
+# -Wno-endif-labels : Needed to prevent warnings in ieee80.c.
+AM_CFLAGS = \
+	-Isrc/include \
+	-D_POSIX_C_SOURCE=200112L \
+	-Wno-endif-labels
 
 EXTRA_DIST=
 
@@ -132,8 +136,8 @@ lib_LTLIBRARIES += src/libespeak-ng.la
 src_libespeak_ng_la_LDFLAGS = -version-info $(SHARED_VERSION) -lpthread -lm \
 	${PCAUDIOLIB_LIBS}
 
-src_libespeak_ng_la_CFLAGS = -Isrc/include -Isrc/include/compat -I src/ucd-tools/src/include \
-	-fPIC -fvisibility=hidden -D _BSD_SOURCE -D_DEFAULT_SOURCE -D _POSIX_C_SOURCE=200112L \
+src_libespeak_ng_la_CFLAGS = -Isrc/include/compat -I src/ucd-tools/src/include \
+	-fPIC -fvisibility=hidden -D _BSD_SOURCE -D_DEFAULT_SOURCE \
 	-pedantic -fno-exceptions -D PATH_ESPEAK_DATA=\"$(DATADIR)\" -DLIBESPEAK_NG_EXPORT \
 	${PCAUDIOLIB_CFLAGS} ${AM_CFLAGS}
 
@@ -199,7 +203,7 @@ endif
 
 src_speak_ng_LDADD   = src/libespeak-ng.la
 src_speak_ng_LDFLAGS = -static -lm ${PCAUDIOLIB_LIBS}
-src_speak_ng_CFLAGS  = -Isrc/libespeak-ng -Isrc/include -D _POSIX_C_SOURCE=200112L ${AM_CFLAGS}
+src_speak_ng_CFLAGS  = -Isrc/libespeak-ng ${AM_CFLAGS}
 src_speak_ng_SOURCES = src/speak-ng.c
 
 bin_PROGRAMS += src/espeak-ng
@@ -209,14 +213,13 @@ man1_MANS += src/espeak-ng.1
 endif
 
 src_espeak_ng_LDADD   = src/libespeak-ng.la ${PCAUDIOLIB_LIBS}
-src_espeak_ng_CFLAGS  = -Isrc/include ${AM_CFLAGS}
 src_espeak_ng_SOURCES = src/espeak-ng.c
 
 ##### tests:
 
 noinst_bin_PROGRAMS += tests/encoding.test
 
-tests_encoding_test_CFLAGS = -Isrc/libespeak-ng -Isrc/include -D _POSIX_C_SOURCE=200112L ${AM_CFLAGS}
+tests_encoding_test_CFLAGS = -Isrc/libespeak-ng ${AM_CFLAGS}
 tests_encoding_test_SOURCES = \
 	src/libespeak-ng/encoding.c \
 	src/libespeak-ng/mnemonics.c \
@@ -225,8 +228,8 @@ tests_encoding_test_SOURCES = \
 noinst_bin_PROGRAMS += tests/tokenizer.test
 
 tests_tokenizer_test_CFLAGS = \
-	-Isrc/libespeak-ng -Isrc/include -Isrc/include/compat -I src/ucd-tools/src/include \
-	-D _POSIX_C_SOURCE=200112L ${AM_CFLAGS}
+	-Isrc/libespeak-ng -Isrc/include/compat -I src/ucd-tools/src/include \
+	${AM_CFLAGS}
 tests_tokenizer_test_SOURCES = \
 	$(UCD_TOOLS_SOURCES) \
 	src/libespeak-ng/encoding.c \