configure log lies when some OpenGL packages are missing

[JuhaSointusalo]

When there are no OpenGL packages installed configure reports the following:

checking for OpenGL library... -L/mingw64/lib -lopengl32
checking for OpenGL Utility library... -L/mingw64/lib -lglu32
...
checking for GLUT library... no
configure: WARNING:
================================================================================
WARNING: Development libraries and headers ("-dev") of {openGL, GLU, glut} needed!

Even though the later message gets it right the earlier log messages are confusing.

If I install freeglut I get no warning but of the files that configure "found" only freeglut_static.a and GL/glut.h exist:

checking for OpenGL Utility library... -L/mingw64/lib -lglu32
checking for fopen in -lXmu... no
checking for fopen in -lXi... no
checking for fopen in -lgdi32... yes
checking for fopen in -lwinmm... yes
checking for GLUT library... -L/mingw64/lib -lfreeglut_static
checking gl.h usability... no
checking gl.h presence... no
checking for gl.h... no
checking glu.h usability... no
checking glu.h presence... no
checking for glu.h... no
checking glut.h usability... no
checking glut.h presence... no
checking for glut.h... no
checking glaux.h usability... no
checking glaux.h presence... no
checking for glaux.h... no
checking GL/gl.h usability... yes
checking GL/gl.h presence... yes
checking for GL/gl.h... yes
checking GL/glu.h usability... yes
checking GL/glu.h presence... yes
checking for GL/glu.h... yes
checking GL/glut.h usability... yes
checking GL/glut.h presence... yes
checking for GL/glut.h... yes
checking GL/glaux.h usability... yes
checking GL/glaux.h presence... yes
checking for GL/glaux.h... yes

[JuhaSointusalo]

After looking around a bit more carefully turns out the files do exist but not in /mingw64/lib as the log says. libopengl32.a and libglu32.a are in /mingw64/x86_64-w64-mingw32/lib/ .

On Linux it's similar:

checking for OpenGL library... -L/usr/local/lib -lGL
checking for OpenGL Utility library... -L/usr/local/lib -lGLU
checking for GLUT library... -L/usr/local/lib -lglut

The files are not in /usr/local/lib but in /usr/lib/x86_64-linux-gnu/.

Even though configure does correctly report if it found or did not find OpenGL libs, I'm leaving this open. I think it would be better if configure doesn't report path or add extra linker flags if the libraries are found in default library directory.