Check libpng directly into third_party/

third_party/libpng/contrib/pngminim/encoder/makefile

+# Makefile for PngMinus (pnm2pngm)
+# Linux / Unix
+
+#CC=cc
+CC=gcc
+LD=$(CC)
+
+# If awk fails try
+# make AWK=nawk
+
+# If cpp fails try
+# make CPP=/lib/cpp
+
+RM=rm -f
+COPY=cp
+
+CPPFLAGS=-I. -DPNG_USER_CONFIG -DNO_GZCOMPRESS -DZ_SOLO -DNO_GZIP
+CFLAGS=-O1 -Wall
+
+C=.c
+O=.o
+L=.a
+E=
+
+# Where to find the source code:
+PNGSRC =../../..
+ZLIBSRC=$(PNGSRC)/../zlib
+PROGSRC=$(PNGSRC)/contrib/pngminus
+
+# Zlib
+ZSRCS  = adler32$(C) compress$(C) crc32$(C) deflate$(C) \
+         trees$(C) zutil$(C)
+
+# Standard headers
+#ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+ZH     = zlib.h crc32.h deflate.h trees.h zutil.h
+
+# Machine generated headers
+ZCONF  = zconf.h
+
+# Headers callers use
+ZINC   = zlib.h $(ZCONF)
+
+# Headers the Zlib source uses
+ZHDRS  = $(ZH) $(ZCONF)
+
+# compress is not required; it is needed to link the zlib
+# code because deflate defines an unused API function deflateBound
+# which itself calls compressBound from compress.
+ZOBJS  = adler32$(O) compress$(O) crc32$(O) deflate$(O) \
+         trees$(O) zutil$(O)
+
+# libpng
+PNGSRCS=png$(C) pngerror$(C) pngget$(C) pngmem$(C) \
+        pngset$(C) pngtrans$(C) pngwio$(C) pngwrite$(C) \
+        pngwtran$(C) pngwutil$(C)
+
+# Standard headers
+PNGH   =png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+
+# Machine generated headers
+PNGCONF=pnglibconf.h
+
+# Headers callers use
+PNGINC= png.h pngconf.h pngusr.h $(PNGCONF)
+
+# Headers the PNG library uses
+PNGHDRS=$(PNGH) $(PNGCONF) pngusr.h
+
+PNGOBJS=png$(O) pngerror$(O) pngget$(O) pngmem$(O) \
+        pngset$(O) pngtrans$(O) pngwio$(O) pngwrite$(O) \
+        pngwtran$(O) pngwutil$(O)
+
+PROGSRCS= pnm2pngm$(C)
+PROGHDRS=
+PROGDOCS=
+PROGOBJS= pnm2pngm$(O)
+
+OBJS    = $(PROGOBJS) $(PNGOBJS) $(ZOBJS)
+
+# implicit make rules -------------------------------------------------------
+
+.c$(O):
+        $(CC) -c $(CPPFLAGS) $(CFLAGS) $<
+
+# dependencies
+
+all: pnm2pngm$(E)
+
+pnm2pngm$(E): $(OBJS)
+        $(LD) -o pnm2pngm$(E) $(OBJS)
+
+# The DFA_XTRA setting turns all libpng options off then
+# turns on those required for this minimal build.
+# The CPP_FLAGS setting causes pngusr.h to be included in
+# both the build of pnglibconf.h and, subsequently, when
+# building libpng itself.
+$(PNGCONF): $(PNGSRC)/scripts/pnglibconf.mak $(ZH)\
+        $(PNGSRC)/scripts/pnglibconf.dfa \
+        $(PNGSRC)/scripts/options.awk pngusr.h pngusr.dfa
+        $(RM) pnglibconf.h pnglibconf.dfn
+        $(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+            srcdir=$(PNGSRC) CPPFLAGS="-DPNG_USER_CONFIG -I."\
+            DFA_XTRA="pngusr.dfa" $@
+
+clean:
+        $(MAKE) -f $(PNGSRC)/scripts/pnglibconf.mak $(MAKEFLAGS)\
+            srcdir=$(PNGSRC) clean
+        $(RM) pnm2pngm$(O)
+        $(RM) pnm2pngm$(E)
+        $(RM) $(OBJS)
+
+# distclean also removes the copied source and headers
+distclean: clean
+        $(RM) -r scripts # historical reasons
+        $(RM) $(PNGSRCS) $(PNGH)
+        $(RM) $(ZSRCS) $(ZH) $(ZCONF)
+        $(RM) $(PROGSRCS) $(PROGHDRS) $(PROGDOCS)
+
+# Header file dependencies:
+$(PROGOBJS): $(PROGHDRS) $(PNGINC) $(ZINC)
+$(PNGOBJS): $(PNGHDRS) $(ZINC)
+$(ZOBJS): $(ZHDRS)
+
+# Gather the source code from the respective directories
+$(PNGSRCS) $(PNGH): $(PNGSRC)/$@
+        $(RM) $@
+        $(COPY) $(PNGSRC)/$@ $@
+
+# No dependency on the ZLIBSRC target so that it only needs
+# to be specified once.
+$(ZSRCS) $(ZH):
+        $(RM) $@
+        $(COPY) $(ZLIBSRC)/$@ $@
+
+# The unconfigured zconf.h varies in name according to the
+# zlib release
+$(ZCONF):
+        $(RM) $@
+        @for f in zconf.h.in zconf.in.h zconf.h; do\
+            test -r $(ZLIBSRC)/$$f &&\
+            echo $(COPY) $(ZLIBSRC)/$$f $@ &&\
+            $(COPY) $(ZLIBSRC)/$$f $@ && exit 0;\
+        done; echo copy: $(ZLIBSRC)/zconf.h not found; exit 1
+
+pnm2pngm.c: $(PROGSRC)/pnm2png.c
+        $(RM) $@
+        $(COPY) $(PROGSRC)/pnm2png.c $@
+
+# End of makefile for pnm2pngm