issues with -R linker paths and Clang

[Riccardo Mottola]

Hi,

on a NetBSD system where I extra use clang instead of standard gcc, I 
have issues building back.
In specific, I noticed when building the xlib backend, but the issue is 
generic, but I did not notice with cairo because it does not link 
directly to certain X libraries, so it went unnoticed.

To run sucessfully, I need this
-Wl,-R/usr/X11R7/lib

so that e.g. Xcursor and other libraries gets found on runtime.

However our configure file generates in config.make this:

GRAPHIC_LIBS=-L/usr/pkg/lib -Wl,-R/usr/pkg/lib -lXft  -lfontconfig 
-L/usr/X11R7/lib -lXcursor -lXfixes -lXmu -lXt -lXext -lX11   -lGL
GRAPHIC_CFLAGS=-D_REENTRANT -I/usr/pkg/include 
-I/usr/X11R7/include/freetype2 -I/usr/X11R7/include 
-I/usr/pkg/include/freetype2 -I/usr/X11R7/include -I/usr/X11R7/include
GRAPHIC_LFLAGS=
X_PRE_LIBS= -lSM -lICE

everything compiles and links, but on run I get unresolved shared 
objects which are in /usr/X11R7/lib

This is all done in configure, but where?

One explanation I found is that it is done automatically and that the 
configure check is bad.
I found this in config.log:

configure:3659: checking for X
configure:3848: result: libraries /usr/X11R7/lib, headers /usr/X11R7/include
configure:3868: checking whether -R must be followed by a space
configure:3884: clang -o conftest -g -O2  -I/System/Library/Headers 
-I/usr/pkg/include  -L/System/Library/Libraries/gnu-gnu-gn
u -L/System/Library/Libraries -Wl,-R/usr/pkg/lib -L/usr/pkg/lib 
conftest.c  -R/usr/X11R7/lib >&5
clang: warning: argument unused during compilation: '-R/usr/X11R7/lib'
configure:3884: $? = 0

then this is used:

configure:3901: clang -o conftest -g -O2  -I/System/Library/Headers 
-I/usr/pkg/include  -L/System/Library/Libraries/gnu-gnu-gn
u -L/System/Library/Libraries -Wl,-R/usr/pkg/lib -L/usr/pkg/lib 
conftest.c  -R /usr/X11R7/lib >&5
clang: warning: argument unused during compilation: '-R'
/usr/X11R7/lib: file not recognized: File format not recognized
clang: error: linker command failed with exit code 1 (use -v to see 
invocation)

the warning is interpreted as failure, the error too and so neither 
option is added.

This is actually a linker directive passed to through the compiler, right?

The check itself is apparently useless for us, since only certain 
compilers require a space after -R (cited is Sun) and since we require 
Objective-C, to my knowledge we can use only clang or gcc as of now (and 
the past 15 years?)

Riccardo