Prefer the system gcc when searching for libraries such as -lm

[perl5.git] / hints / linux.sh

diff --git a/hints/linux.sh b/hints/linux.sh
index ac27f23..d0ac9fa 100644 (file)
--- a/hints/linux.sh
+++ b/hints/linux.sh
@@ -18,6 +18,9 @@
 # No version of Linux supports setuid scripts.
 d_suidsafe='undef'
 
+# No version of Linux needs libutil for perl.
+i_libutil='undef'
+
 # Debian and Red Hat, and perhaps other vendors, provide both runtime and
 # development packages for some libraries.  The runtime packages contain shared
 # libraries with version information in their names (e.g., libgdbm.so.1.7.3);
@@ -151,6 +154,34 @@ case "$optimize" in
     ;;
 esac
 
+# Ubuntu 11.04 (and later, presumably) doesn't keep most libraries
+# (such as -lm) in /lib or /usr/lib.  So we have to ask gcc to tell us
+# where to look.  We don't want gcc's own libraries, however, so we
+# filter those out.
+# This could be conditional on Unbuntu, but other distributions may
+# follow suit, and this scheme seems to work even on rather old gcc's.
+# This unconditionally uses gcc because even if the user is using another
+# compiler, we still need to find the math library and friends, and I don't
+# know how other compilers will cope with that situation.
+# Morever, if the user has their own gcc earlier in $PATH than the system gcc,
+# we don't want its libraries. So we try to prefer the system gcc
+# Still, as an escape hatch, allow Configure command line overrides to
+# plibpth to bypass this check.
+if [ -x /usr/bin/gcc ] ; then
+    gcc=/usr/bin/gcc
+else
+    gcc=gcc
+fi
+
+case "$plibpth" in
+'') plibpth=`$gcc -print-search-dirs | grep libraries |
+       cut -f2- -d= | tr ':' $trnl | grep -v 'gcc' | sed -e 's:/$::'`
+    set X $plibpth # Collapse all entries on one line
+    shift
+    plibpth="$*"
+    ;;
+esac
+
 # Are we using ELF?  Thanks to Kenneth Albanowski <kjahds@kjahds.com>
 # for this test.
 cat >try.c <<'EOM'