configure: fix build with Clang on Haiku.

diff --git a/aclocal.m4 b/aclocal.m4
index 5dfe6ad4704567ebad2830c56f105be1b3301942..1a97a7253cf3799c142e27c5b2e14c73b910e9d3 100644 (file)
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -82,6 +82,32 @@ dnl
 AC_DEFUN(AC_LBL_C_INIT,
 [
     AC_BEFORE([$0], [AC_LBL_DEVEL])
+    #
+    # Changes to copt that are required even for compilers that appear
+    # to be GCC (note that not all compilers that apper to be GCC
+    # are, in fact, GCC; Clang, for example, looks enough like GCC
+    # that the autoconf tests for the C compiler set GCC to yes).
+    #
+    case "$host_os" in
+
+    haiku*)
+           #
+           # On Haiku, all executables are built as shared objects,
+           # and must have their code build as PIC.
+           #
+           # At least some versions of Haiku's GCC default to PIC,
+           # with a -fno-pic option for cases where that's not desired.
+           #
+           # Clang hasn't been modified in that fashion, so Clang
+           # builds of tcpdump fail.
+           #
+           # Force the use of -fPIC (even for GCC; adding -fPIC for GCC
+           # won't break anything).
+           #
+           $1="$$1 -fPIC"
+           ;;
+    esac
+
     if test "$GCC" = yes ; then
            #
            # -Werror forces warnings to be errors.
@@ -98,6 +124,9 @@ AC_DEFUN(AC_LBL_C_INIT,
                    # This is assumed either to be GCC or clang, both
                    # of which use -Werror to force warnings to be errors.
                    #
+                   # XXX - they also both cause GCC to be set to yes,
+                   # so we should never get here in the first place.
+                   #
                    ac_lbl_cc_force_warning_errors=-Werror
                    ;;