CPPFLAGS. This allow build Mutt with Bruno's libiconv and
--prefix=/usr on glibc-2.1.2 systems.
From "Andrew W. Nosenko" <awn@bcs.zp.ua>.
DEFS=-DPKGDATADIR=\"$(pkgdatadir)\" -DSYSCONFDIR=\"$(sysconfdir)\" \
-DBINDIR=\"$(bindir)\" -DHAVE_CONFIG_H=1
-INCLUDES=-I. -I$(top_srcdir) $(IMAP_INCLUDES) -Iintl -I$(includedir)
+INCLUDES=-I. -I$(top_srcdir) $(IMAP_INCLUDES) -Iintl
+
+CPPFLAGS=@CPPFLAGS@ -I$(includedir)
non_us_sources = pgp.c pgpinvoke.c pgpkey.c pgplib.c sha1.c \
pgpmicalg.c gnupgparse.c sha1.h \