Rename to header makefile fragements to .mk

The opus_headers.txt, etc. files are makefile
fragments defining variables with a list of
required header files for the build. As such
they should use the .mk filename extension,
just like opus_sources.mk, etc.

Makefile.am

@@ -16,9 +16,9 @@ else
 SILK_SOURCES += $(SILK_SOURCES_FLOAT)
 endif
 
-include celt_headers.txt
-include silk_headers.txt
-include opus_headers.txt
+include celt_headers.mk
+include silk_headers.mk
+include opus_headers.mk
 
 libopus_la_SOURCES = $(CELT_SOURCES) $(SILK_SOURCES) $(OPUS_SOURCES)
 

doc/build_draft.sh

@@ -18,8 +18,8 @@ mkdir "${destdir}/silk/fixed"
 mkdir "${destdir}/celt"
 mkdir "${destdir}/include"
 for f in `cat "${toplevel}"/opus_sources.mk "${toplevel}"/celt_sources.mk \
- "${toplevel}"/silk_sources.mk "${toplevel}"/opus_headers.txt \
- "${toplevel}"/celt_headers.txt "${toplevel}"/silk_headers.txt \
+ "${toplevel}"/silk_sources.mk "${toplevel}"/opus_headers.mk \
+ "${toplevel}"/celt_headers.mk "${toplevel}"/silk_headers.mk \
  | grep '\.[ch]' | sed -e 's/^.*=//' -e 's/\\\\//'` ; do
   cp -a "${toplevel}/${f}" "${destdir}/${f}"
 done