diff --git a/lib/mcconfig/Makefile.am b/lib/mcconfig/Makefile.am
index 2b581378d..0cabd2f8a 100644
--- a/lib/mcconfig/Makefile.am
+++ b/lib/mcconfig/Makefile.am
@@ -7,4 +7,4 @@ libmcconfig_la_SOURCES = \
 	set.c \
 	paths.c
 
-AM_CFLAGS = -I$(top_srcdir) $(GLIB_CFLAGS)
+AM_CPPFLAGS = -I$(top_srcdir) $(GLIB_CFLAGS)
diff --git a/lib/strutil/Makefile.am b/lib/strutil/Makefile.am
index 9c36a1977..cf907489e 100644
--- a/lib/strutil/Makefile.am
+++ b/lib/strutil/Makefile.am
@@ -8,4 +8,4 @@ libmcstrutil_la_SOURCES = \
 	strutilutf8.c \
 	strverscmp.c
 
-AM_CFLAGS = -I$(top_srcdir) $(GLIB_CFLAGS)
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
diff --git a/lib/tty/Makefile.am b/lib/tty/Makefile.am
index 0b7c11f86..d0f5bfcef 100644
--- a/lib/tty/Makefile.am
+++ b/lib/tty/Makefile.am
@@ -22,11 +22,11 @@ TTY_SRC = \
 
 libmctty_la_SOURCES = $(TTY_SRC) $(TTY_SCREEN_SRC)
 
-AM_CFLAGS = -I$(top_srcdir)
+AM_CPPFLAGS = -I$(top_srcdir)
 
 if HAVE_GMODULE
-AM_CFLAGS += $(GMODULE_CFLAGS)
+AM_CPPFLAGS += $(GMODULE_CFLAGS)
 else
-AM_CFLAGS += $(GLIB_CFLAGS)
+AM_CPPFLAGS += $(GLIB_CFLAGS)
 endif
 
diff --git a/lib/vfs/Makefile.am b/lib/vfs/Makefile.am
index 8d03bfcb0..87a51c641 100644
--- a/lib/vfs/Makefile.am
+++ b/lib/vfs/Makefile.am
@@ -1,6 +1,6 @@
 noinst_LTLIBRARIES = libmcvfs.la
 
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 libmcvfs_la_SOURCES = \
 	direntry.c		\
diff --git a/src/consaver/Makefile.am b/src/consaver/Makefile.am
index 2800dbbf4..ba446c13b 100644
--- a/src/consaver/Makefile.am
+++ b/src/consaver/Makefile.am
@@ -4,4 +4,4 @@ pkglibexec_PROGRAMS = cons.saver
 
 cons_saver_SOURCES = cons.saver.c
 
-AM_CFLAGS= -I$(top_srcdir)
+AM_CPPFLAGS = -I$(top_srcdir)
diff --git a/src/vfs/Makefile.am b/src/vfs/Makefile.am
index 7418bddf1..4dc288940 100644
--- a/src/vfs/Makefile.am
+++ b/src/vfs/Makefile.am
@@ -1,6 +1,6 @@
 noinst_LTLIBRARIES = libmc-vfs.la
 
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 libmc_vfs_la_SOURCES = plugins_init.c plugins_init.h
 
 SUBDIRS = local
diff --git a/src/vfs/cpio/Makefile.am b/src/vfs/cpio/Makefile.am
index 987662527..a7806f8a0 100644
--- a/src/vfs/cpio/Makefile.am
+++ b/src/vfs/cpio/Makefile.am
@@ -1,4 +1,5 @@
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-cpio.la
 
diff --git a/src/vfs/extfs/Makefile.am b/src/vfs/extfs/Makefile.am
index e68cce27b..39762a30f 100644
--- a/src/vfs/extfs/Makefile.am
+++ b/src/vfs/extfs/Makefile.am
@@ -1,8 +1,10 @@
 SUBDIRS = helpers
 DIST_SUBDIRS = helpers
 
-AM_CPPFLAGS = -DLIBEXECDIR=\""$(libexecdir)/@PACKAGE@/"\"
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+AM_CPPFLAGS = \
+	-DLIBEXECDIR=\""$(libexecdir)/@PACKAGE@/"\" \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-extfs.la
 
diff --git a/src/vfs/fish/Makefile.am b/src/vfs/fish/Makefile.am
index d982cbd84..4f3ca874c 100644
--- a/src/vfs/fish/Makefile.am
+++ b/src/vfs/fish/Makefile.am
@@ -1,8 +1,10 @@
 SUBDIRS = helpers
 DIST_SUBDIRS = helpers
 
-AM_CPPFLAGS = -DLIBEXECDIR=\""$(libexecdir)/@PACKAGE@/"\"
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+AM_CPPFLAGS = \
+	-DLIBEXECDIR=\""$(libexecdir)/@PACKAGE@/"\" \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-fish.la
 
diff --git a/src/vfs/ftpfs/Makefile.am b/src/vfs/ftpfs/Makefile.am
index 69af7ba43..136e2c956 100644
--- a/src/vfs/ftpfs/Makefile.am
+++ b/src/vfs/ftpfs/Makefile.am
@@ -1,4 +1,5 @@
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-ftpfs.la
 
diff --git a/src/vfs/local/Makefile.am b/src/vfs/local/Makefile.am
index aec17d3d5..0176d46e6 100644
--- a/src/vfs/local/Makefile.am
+++ b/src/vfs/local/Makefile.am
@@ -1,4 +1,5 @@
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-local.la
 
diff --git a/src/vfs/sfs/Makefile.am b/src/vfs/sfs/Makefile.am
index 50d81c9e1..2271c5320 100644
--- a/src/vfs/sfs/Makefile.am
+++ b/src/vfs/sfs/Makefile.am
@@ -1,4 +1,5 @@
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-sfs.la
 
diff --git a/src/vfs/smbfs/Makefile.am b/src/vfs/smbfs/Makefile.am
index 132838afa..1b4b224b8 100644
--- a/src/vfs/smbfs/Makefile.am
+++ b/src/vfs/smbfs/Makefile.am
@@ -2,8 +2,10 @@ DIST_SUBDIRS =
 
 SUBDIRS = helpers
 
-AM_CPPFLAGS = -DCONFIGDIR=\""@smbconfigdir@"\"
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+AM_CPPFLAGS = \
+	-DCONFIGDIR=\""@smbconfigdir@"\" \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-smbfs.la
 
diff --git a/src/vfs/tar/Makefile.am b/src/vfs/tar/Makefile.am
index 4b79c295e..200b7bf64 100644
--- a/src/vfs/tar/Makefile.am
+++ b/src/vfs/tar/Makefile.am
@@ -1,4 +1,5 @@
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-tar.la
 
diff --git a/src/vfs/undelfs/Makefile.am b/src/vfs/undelfs/Makefile.am
index f0e70095a..4e7a77dc5 100644
--- a/src/vfs/undelfs/Makefile.am
+++ b/src/vfs/undelfs/Makefile.am
@@ -1,4 +1,5 @@
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
+
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir)
 
 noinst_LTLIBRARIES = libvfs-undelfs.la
 
diff --git a/tests/lib/Makefile.am b/tests/lib/Makefile.am
index 959e618d1..c02d7f709 100644
--- a/tests/lib/Makefile.am
+++ b/tests/lib/Makefile.am
@@ -1,7 +1,8 @@
 SUBDIRS = . mcconfig search vfs
 
-AM_CFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir) @CHECK_CFLAGS@
-LIBS=@CHECK_LIBS@  $(top_builddir)/lib/libmc.la
+AM_CPPFLAGS = $(GLIB_CFLAGS) -I$(top_srcdir) @CHECK_CFLAGS@
+
+LIBS = @CHECK_LIBS@ $(top_builddir)/lib/libmc.la
 
 TESTS = \
 	library_independ \
diff --git a/tests/lib/mcconfig/Makefile.am b/tests/lib/mcconfig/Makefile.am
index 0894abc5b..522902e91 100644
--- a/tests/lib/mcconfig/Makefile.am
+++ b/tests/lib/mcconfig/Makefile.am
@@ -1,6 +1,9 @@
 
-AM_CPPFLAGS = -DWORKDIR=\"$(abs_builddir)\"
-AM_CFLAGS = -I$(top_srcdir) $(GLIB_CFLAGS) @CHECK_CFLAGS@
+AM_CPPFLAGS = \
+	-DWORKDIR=\"$(abs_builddir)\" \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir) \
+	@CHECK_CFLAGS@
 
 AM_LDFLAGS = @TESTS_LDFLAGS@
 
diff --git a/tests/lib/search/Makefile.am b/tests/lib/search/Makefile.am
index db8931713..2ce976104 100644
--- a/tests/lib/search/Makefile.am
+++ b/tests/lib/search/Makefile.am
@@ -1,5 +1,11 @@
-AM_CFLAGS = -I$(top_srcdir)/lib/search $(GLIB_CFLAGS) -I$(top_srcdir) @CHECK_CFLAGS@
-LIBS=@CHECK_LIBS@  $(top_builddir)/lib/libmc.la
+
+AM_CPPFLAGS = \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir) \
+	-I$(top_srcdir)/lib/search \
+	@CHECK_CFLAGS@
+
+LIBS = @CHECK_LIBS@ $(top_builddir)/lib/libmc.la
 
 TESTS = \
 	regex_replace_esc_seq \
diff --git a/tests/lib/vfs/Makefile.am b/tests/lib/vfs/Makefile.am
index 9dbe46c00..31d6cea0a 100644
--- a/tests/lib/vfs/Makefile.am
+++ b/tests/lib/vfs/Makefile.am
@@ -1,6 +1,10 @@
 
-AM_CPPFLAGS = -DTEST_SHARE_DIR=\"$(abs_srcdir)\"
-AM_CFLAGS = -I$(top_srcdir) -I$(top_srcdir)/lib/vfs $(GLIB_CFLAGS) @CHECK_CFLAGS@
+AM_CPPFLAGS = \
+	-DTEST_SHARE_DIR=\"$(abs_srcdir)\" \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir) \
+	-I$(top_srcdir)/lib/vfs \
+	@CHECK_CFLAGS@
 
 AM_LDFLAGS = @TESTS_LDFLAGS@
 
diff --git a/tests/src/filemanager/Makefile.am b/tests/src/filemanager/Makefile.am
index 460193317..96086f0fa 100644
--- a/tests/src/filemanager/Makefile.am
+++ b/tests/src/filemanager/Makefile.am
@@ -1,4 +1,9 @@
-AM_CFLAGS = -I$(top_srcdir)/lib/vfs $(GLIB_CFLAGS) -I$(top_srcdir) @CHECK_CFLAGS@
+
+AM_CPPFLAGS = \
+	$(GLIB_CFLAGS) \
+	-I$(top_srcdir) \
+	-I$(top_srcdir)/lib/vfs \
+	@CHECK_CFLAGS@
 
 AM_LDFLAGS = @TESTS_LDFLAGS@