Index: gmic-1.5.8.4/src/Makefile
===================================================================
--- gmic-1.5.8.4.orig/src/Makefile
+++ gmic-1.5.8.4/src/Makefile
@@ -209,8 +209,11 @@ FFTW_LDFLAGS = -lfftw3 -lfftw3_threads
 ifeq ($(OSTYPE),msys)
 FFTW_LDFLAGS = -lfftw3-3
 endif
 
+OPENMP_CFLAGS = -fopenmp -Dcimg_use_openmp
+OPENMP_LDFLAGS = -fopenmp
+
 # Flags to enable the use of the BOARD library.
 # This requires the presence of the BOARD include and library files.
 # (no packages exist for Debian at this time).
 BOARD_CFLAGS = -Dcimg_use_board
@@ -222,12 +225,14 @@ BOARD_LDFLAGS = -lboard
 
 # Unix : Standard build.
 STD_UNIX_CFLAGS = $(MANDATORY_CFLAGS) $(CHECKIMAGE_CFLAGS) $(PARALLEL_CFLAGS) $(X11_CFLAGS) $(XSHM_CFLAGS) $(PNG_CFLAGS) \
                   $(JPEG_CFLAGS) $(TIFF_CFLAGS) $(ZLIB_CFLAGS) \
-	  	  $(EXR_CFLAGS) $(FFTW_CFLAGS) # $(OPENCV_CFLAGS) $(FFMPEG_CFLAGS) # $(MAGICK_CFLAGS)
+	  	  $(EXR_CFLAGS) $(FFTW_CFLAGS) $(OPENMP_CFLAGS) \
+		  # $(OPENCV_CFLAGS) $(FFMPEG_CFLAGS) # $(MAGICK_CFLAGS)
 STD_UNIX_LDFLAGS = $(MANDATORY_LDFLAGS) $(PARALLEL_LDFLAGS) $(X11_LDFLAGS) $(XSHM_LDFLAGS) $(PNG_LDFLAGS) \
 		   $(JPEG_LDFLAGS) $(TIFF_LDFLAGS) $(ZLIB_LDFLAGS) \
-	           $(EXR_LDFLAGS) $(FFTW_LDFLAGS) # $(OPENCV_LDFLAGS) $(FFMPEG_LDFLAGS) # $(MAGICK_LDFLAGS)
+	           $(EXR_LDFLAGS) $(FFTW_LDFLAGS) $(OPENMP_LDFLAGS) \
+		   # $(OPENCV_LDFLAGS) $(FFMPEG_LDFLAGS) # $(MAGICK_LDFLAGS)
 
 # Unix : Minimal build.
 MINIMAL_UNIX_CFLAGS = $(MANDATORY_CFLAGS) $(CHECKIMAGE_CFLAGS) $(PARALLEL_CFLAGS) $(DEBUG_CFLAGS) $(X11_CFLAGS) $(XSHM_CFLAGS) \
 	              ${TIFF_CFLAGS} ${PNG_CFLAGS} $(ZLIB_CFLAGS) $(FFTW_CFLAGS) # $(OPENCV_CFLAGS)