Make peach with doxygen >= 1.8.8 (#131)

Doxygen >= 1.8.8 skips files with unknown (or missing) extension,
whereas previously they were assumed C-like. Rename the Doxyheader
files to Doxyheader.h to keep the C-association, adjust makefiles.

Thanks to Pavlina Varekova for chasing this down!

Makefile.am

@@ -258,7 +258,7 @@ MAINTAINERCLEANFILES = ChangeLog
 # Build hacking docs only on request
 if HACKINGDOCS
 if DOXYGEN
-doc/hacking.doxy: doc/hacking.doxy.in doc/hacking/Doxyheader Makefile.am
+doc/hacking.doxy: doc/hacking.doxy.in doc/hacking/Doxyheader.h Makefile.am
 	$(SED) \
 	  -e "s,\@top_srcdir\@/,$(top_srcdir)/,g" \
 	  -e "s,[@]HAVE_DOT[@],$(HAVE_DOT)," \
@@ -271,11 +271,11 @@ doc/hacking/html/index.html: doc/hacking.doxy rpmpopt-@VERSION@
 noinst_DATA += doc/hacking/html/index.html
 endif
 endif
-EXTRA_DIST += doc/hacking.doxy.in doc/hacking/Doxyheader
+EXTRA_DIST += doc/hacking.doxy.in doc/hacking/Doxyheader.h
 
 # Always build librpm docs
 if DOXYGEN
-doc/librpm.doxy: doc/librpm.doxy.in doc/librpm/Doxyheader Makefile.am configure.ac $(pkginclude_HEADERS)
+doc/librpm.doxy: doc/librpm.doxy.in doc/librpm/Doxyheader.h Makefile.am configure.ac $(pkginclude_HEADERS)
 	files=`echo " $(pkginclude_HEADERS)" | $(SED) -e "s, , \@top_srcdir\@/,g"`; \
 	$(SED) -e "s,[@]pkginclude_HEADERS[@],$$files," \
 	  -e "s,\@top_srcdir\@/,$(top_srcdir)/,g" \
@@ -288,7 +288,7 @@ doc/librpm/html/index.html: doc/librpm.doxy
 	@DOXYGEN@ doc/librpm.doxy
 noinst_DATA += doc/librpm/html/index.html
 endif
-EXTRA_DIST += doc/librpm.doxy.in doc/librpm/Doxyheader
+EXTRA_DIST += doc/librpm.doxy.in doc/librpm/Doxyheader.h
 EXTRA_DIST += doc/librpm/html
 
 if WITH_INTERNAL_DB

doc/hacking.doxy.in

@@ -753,7 +753,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @top_srcdir@/doc/hacking/Doxyheader \
+INPUT                  = @top_srcdir@/doc/hacking/Doxyheader.h \
                          @top_srcdir@/config.h \
                          @top_srcdir@/debug.h \
                          @top_srcdir@/macros \

doc/librpm.doxy.in

@@ -753,7 +753,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @top_srcdir@/doc/librpm/Doxyheader \
+INPUT                  = @top_srcdir@/doc/librpm/Doxyheader.h \
                          @pkginclude_HEADERS@
 
 # This tag can be used to specify the character encoding of the source files