[hackers] [farbfeld] don't link against unneeded libs || Hiltjo Posthuma

[git]

commit 7f295f8c100a504c305d537bd3fde6492f15ef7a
Author:     Hiltjo Posthuma <hil...@codemadness.org>
AuthorDate: Thu Mar 24 19:09:41 2016 +0100
Commit:     FRIGN <d...@frign.de>
CommitDate: Sun Apr 3 20:39:13 2016 +0200

    don't link against unneeded libs
    
    - jpg2ff requires libjpeg
    - ff2png, png2ff requires libpng (and libz)
    - ff2ppm has no dependencies

diff --git a/Makefile b/Makefile
index 63b4d0a..ac85a0f 100644
--- a/Makefile
+++ b/Makefile
@@ -8,11 +8,21 @@ HDR = arg.h
 MAN1 = 2ff.1 ${BIN:=.1}
 MAN5 = farbfeld.5
 
-all: png2ff ff2png jpg2ff ff2ppm
+all: ${BIN}
+
+png2ff ff2png:
+       @echo CC $@
+       @${CC} -o $@ ${CFLAGS} ${CPPFLAGS} -L${PNGLIB} -lpng -I${PNGINC} \
+               ${LDFLAGS} $@.c
+
+jpg2ff:
+       @echo CC $@
+       @${CC} -o $@ ${CFLAGS} ${CPPFLAGS} -L${JPGLIB} -ljpeg -I${JPGINC} \
+               ${LDFLAGS} $@.c
 
 .c:
-       @echo CC $<
-       @${CC} -o $@ ${CFLAGS} ${LIBS} ${LDFLAGS} $<
+       @echo CC $@
+       @${CC} -o $@ ${CFLAGS} ${CPPFLAGS} ${LDFLAGS} $<
 
 clean:
        @echo cleaning
diff --git a/config.mk b/config.mk
index 94a4570..4ecba54 100644
--- a/config.mk
+++ b/config.mk
@@ -13,12 +13,12 @@ PNGINC = /usr/local/include
 JPGLIB = /usr/local/lib
 JPGINC = /usr/local/include
 
-INCS = -I${PNGINC} -I${JPGINC}
-LIBS = -L${PNGLIB} -L${JPGLIB} -lpng -ljpeg
+INCS =
+LIBS =
 
 # flags
 CPPFLAGS = -D_DEFAULT_SOURCE
-CFLAGS   = -std=c99 -pedantic -Wall -Os ${INCS} ${CPPFLAGS}
+CFLAGS   = -std=c99 -pedantic -Wall -Os ${INCS}
 LDFLAGS  = -s ${LIBS}
 
 # compiler and linker