cannot link glew under xcode4, macosx lion - glew

Question

Using glew, I'm trying to link the simple program
#include </usr/include/GL/glew.h>
int main (int argc, const char * argv[])
{
glewInit();
return 0;
}
in XCode 4, under OSX Lion, which reports the error:
ld: library not found for -lGLEW.1.7.0
Command /Developer/usr/bin/clang++ failed with exit code 1
however, the error output also reports the following flags for the linker
-mmacosx-version-min=10.7 -L/usr/lib -lGLEW.1.7.0 -lglfw -framework OpenGL -framework Cocoa
and indeed, libGLEW.1.7.0 does reside in /usr/lib
Moreover, if I try to build the program by hand, with
gcc -L/usr/lib -lGLEW.1.7.0 main.cpp
I get an a.out file without any errors reported (which if run causes a segmentation fault, but maybe that's to be expected)
Any ideas on what might be causing XCode to produce this error and how it could be avoided?

Answer 1

Built and installed GLEW myself and had the same issue with plain gcc inside a makefile on OS X with compilation of code from https://github.com/jckarter/hello-gl
The following steps resolved the issue:
I found my GLEW libs (libGLEW.a and libGLEW.dylib) installed in /usr/lib directory (it definitely was there owned by root with r permissions for others). Tried to change GLEW_LIB variable from the makefile to /usr/lib but still got ld: library not found for -lGLEW
after that I tried to link compiled program against static library directly (without -l flag) - for that I removed -lGLEW from gcc command and changed it to direct link t library /usr/lib/libGLEW.a - it compiled and linked fine
Ok - it's a work around to try first
Then I created two links to my libraries with the following commands:
ln -s /usr/lib/libGLEW.a /usr/local/lib/libGLEW.a
ln -s /usr/lib/libGLEW.dylib /usr/local/lib/libGLEW.dylib
and finally got it working with original makefile (only changed GLEW_LIB variable to /usr/local/lib).
Probably GLEW's make install should place libraries to /usr/local/lib directly.

Answer 2

(I have removed this from an edit to the question and posted it as an answer, as per leppie's suggestion)
I might have found the answer in some details I had considered unimportant in my original post. So here goes, in case others might encounter a similar problem.
Apparently, XCode4 projects use clang++ by default, which in the link phase accepts a parameter -isysroot (which apparently ld does not accept).
Now, if in your build settings (as was my case) your Base SDK has been defined as something other than Current Mac OS, the parameter -isysroot will be introduced with the value of a directory pointing to that SDK, thus (this is my guess) prepending this to all other lib directories you might be including with -L.
In my case, -L/usr/lib was effectively turning into -L/Developer/SDKs/MacOSX10.7.sdk/usr/lib which does exist and did not contain libGLEW, hence the error "library not found"