Use CFLAGS_SL while probing linkability of libperl.

tglsfdc · tglsfdc · commit ca658c91ae72 · 2019-10-21T13:52:25.000-04:00
On recent Red Hat platforms (at least RHEL 8 and Fedora 30, maybe older), configure's probe for libperl failed if the user forces CFLAGS to be -O0. This is because some code in perl's inline.h fails to be optimized away at -O0, and said code doesn't work if compiled without -fPIC. To fix, add CFLAGS_SL to the compile flags used during the libperl probe. This is a better simulation of the way that plperl is built, anyway, so it might forestall other issues in future. Per gripe from Kyotaro Horiguchi. Back-patch to all supported branches, since people might want to build older branches on these platforms. Discussion: https://postgr.es/m/20191010.144533.263180400.horikyota.ntt@gmail.com
diff --git a/configure b/configure
@@ -18615,6 +18615,10 @@ fi
   # On most platforms, if perl.h is there then libperl.so will be too, but at
   # this writing Debian packages them separately.  There is no known reason to
   # waste cycles on separate probes for the Tcl or Python libraries, though.
+  # On some Red Hat platforms, the link attempt can fail if we don't use
+  # CFLAGS_SL while building the test program.
+  ac_save_CFLAGS=$CFLAGS
+  CFLAGS="$CFLAGS $CFLAGS_SL"
   pgac_save_LIBS=$LIBS
   LIBS="$perl_embed_ldflags"
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libperl" >&5
@@ -18644,6 +18648,7 @@ fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext conftest.$ac_ext
   LIBS=$pgac_save_LIBS
+  CFLAGS=$ac_save_CFLAGS
   CPPFLAGS=$ac_save_CPPFLAGS
 fi
 
diff --git a/configure.in b/configure.in
@@ -2258,6 +2258,10 @@ if test "$with_perl" = yes; then
   # On most platforms, if perl.h is there then libperl.so will be too, but at
   # this writing Debian packages them separately.  There is no known reason to
   # waste cycles on separate probes for the Tcl or Python libraries, though.
+  # On some Red Hat platforms, the link attempt can fail if we don't use
+  # CFLAGS_SL while building the test program.
+  ac_save_CFLAGS=$CFLAGS
+  CFLAGS="$CFLAGS $CFLAGS_SL"
   pgac_save_LIBS=$LIBS
   LIBS="$perl_embed_ldflags"
   AC_MSG_CHECKING([for libperl])
@@ -2269,6 +2273,7 @@ if test "$with_perl" = yes; then
     [AC_MSG_RESULT(no)
      AC_MSG_ERROR([libperl library is required for Perl])])
   LIBS=$pgac_save_LIBS
+  CFLAGS=$ac_save_CFLAGS
   CPPFLAGS=$ac_save_CPPFLAGS
 fi
 
