Don't use @executable_path, it messed up linking against nspr from e.g.
nss.

--- a/configure.in
+++ b/configure.in
@@ -1007,7 +1007,7 @@
             ;;
     esac
     DSO_CFLAGS=-fPIC
-    DSO_LDOPTS='-dynamiclib -compatibility_version 1 -current_version 1 -all_load -install_name @executable_path/$@ -headerpad_max_install_names'
+    DSO_LDOPTS='-dynamiclib -compatibility_version 1 -current_version 1 -all_load -install_name $(libdir)/$@ -headerpad_max_install_names'
     _OPTIMIZE_FLAGS=-O2
     MKSHLIB='$(CC) $(DSO_LDOPTS) -o $@'
     STRIP="$STRIP -x -S"
--- a/configure
+++ b/configure
@@ -1007,7 +1007,7 @@
             ;;
     esac
     DSO_CFLAGS=-fPIC
-    DSO_LDOPTS='-dynamiclib -compatibility_version 1 -current_version 1 -all_load -install_name @executable_path/$@ -headerpad_max_install_names'
+    DSO_LDOPTS='-dynamiclib -compatibility_version 1 -current_version 1 -all_load -install_name $(libdir)/$@ -headerpad_max_install_names'
     _OPTIMIZE_FLAGS=-O2
     MKSHLIB='$(CC) $(DSO_LDOPTS) -o $@'
     STRIP="$STRIP -x -S"