Arrange Makefile

Let the user specify his own C and LD FLAGS.
Remove unuseful and non portable CFLAGS like pendantic and Wall.

config.mk

@@ -5,8 +5,8 @@ VERSION = 2.0
 
 # paths
 PREFIX = /usr/local
-MANPREFIX = ${PREFIX}/share/man
-LIBPREFIX = ${PREFIX}/lib/surf
+MANPREFIX = $(PREFIX)/share/man
+LIBPREFIX = $(PREFIX)/lib/surf
 
 X11INC = /usr/X11R6/include
 X11LIB = /usr/X11R6/lib
@@ -15,17 +15,17 @@ GTKINC = `pkg-config --cflags gtk+-3.0 webkit2gtk-4.0`
 GTKLIB = `pkg-config --libs gtk+-3.0 webkit2gtk-4.0`
 
 # includes and libs
-INCS = -I. -I/usr/include -I${X11INC} ${GTKINC}
-LIBS = -L/usr/lib -lc -L${X11LIB} -lX11 ${GTKLIB} -lgthread-2.0
+INCS = -I$(X11INC) $(GTKINC)
+LIBS = -L$(X11LIB) -lX11 $(GTKLIB) -lgthread-2.0
 
 # flags
 CPPFLAGS = -DVERSION=\"${VERSION}\" -DWEBEXTDIR=\"${LIBPREFIX}\" -D_DEFAULT_SOURCE
-CFLAGS = -std=c99 -pedantic -Wall -Os ${INCS} ${CPPFLAGS}
-LDFLAGS = -s ${LIBS}
+SURF_CFLAGS = $(INCS) $(CPPFLAGS) $(CFLAGS)
+SURF_LDFLAGS = $(LIBS) $(LDFLAGS)
 
 # Solaris
-#CFLAGS = -fast ${INCS} -DVERSION=\"${VERSION}\"
-#LDFLAGS = ${LIBS}
+#CFLAGS = -fast $(INCS) -DVERSION=\"$(VERSION)\"
+#LDFLAGS = $(LIBS)
 
 # compiler and linker
-CC = cc
+#CC = c99