On 01/14/2010 12:10 PM, Ralf Wildenhues wrote: > Hi Philip, > > * Philip A. Prindeville wrote on Thu, Jan 14, 2010 at 02:43:49AM CET: >> Silly question, but I was working on a particular project >> (dahdi-tools) and I noticed that the value of LD that was passed to >> "configure" didn't get saved into "makeopts". >> >> I hacked the configure.ac file as: > [...] >> +AC_SUBST(LD) >> + > [...] >> and this seems to work, but this left me wondering why "LD" isn't a >> precious variable, just like "CC" is. > > First off, a naming nit: in the Autoconf lingo, AC_SUBST makes a > variable be "substituted", i.e., occurrences of @LD@ in <file>.in for > <file> listed in an AC_CONFIG_FILES macro are replaced by config.status > with the value of $LD. "Precious" variables on the other hand are those > substituted variables which are also saved and restored for an eventual > `./config.status --recheck' triggering another configure run. > > Now, by default, LD is neither precious nor substituted, because > nowadays the linker is rarely needed directly: most packages come by > with using the compiler driver for linking, who then calls the linker. > > Libtool, by the way, uses $LD sometimes, and AC_PROG_LIBTOOL causes $LD > to be substituted. > >> Looking at the contents of /usr/share/autoconf/autoconf/ for autoconf >> 2.63, I'm not seeing \<LD\> anywhere. >> >> Is that an oversight? I ask because in a cross-compilation >> environment, getting CC and LD right are equally important. > > Sure, but why would $LD be more important in cross compilation setups > than in native ones? The cross-compiler usually calls the right linker. > > Cheers, > Ralf Because I'm encountering Makefiles that call $(LD) directly, and default LD to "ld" unless you explicitly override it (and not setting it to $(CC)). Overriding it every time I call "make" is a pain, and besides, I have a Makefile macro that contains all the usual values that I pass into "./configure" (i.e. HOSTCC="gcc" CC="$(TARGET_CC)" CFLAGS="$(TARGET_CFLAGS)" LD="$(TARGET_LD)" LDFLAGS="$(TARGET_LDFLAGS)" etc). So specifying it during "configure" and then having "make all" and "make install" not need to have LD="$(TARGET_LD)" passed in would be a win. -Philip _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
