File ffmpeg-libglslang-detection.patch of Package ffmpeg-4

Index: ffmpeg-4.4.3/configure
===================================================================
--- ffmpeg-4.4.3.orig/configure
+++ ffmpeg-4.4.3/configure
@@ -6377,7 +6377,12 @@ enabled fontconfig        && enable libf
 enabled libfontconfig     && require_pkg_config libfontconfig fontconfig "fontconfig/fontconfig.h" FcInit
 enabled libfreetype       && require_pkg_config libfreetype freetype2 "ft2build.h FT_FREETYPE_H" FT_Init_FreeType
 enabled libfribidi        && require_pkg_config libfribidi fribidi fribidi.h fribidi_version_info
-enabled libglslang        && require_cpp libglslang glslang/SPIRV/GlslangToSpv.h "glslang::TIntermediate*" -lglslang -lMachineIndependent -lOSDependent -lHLSL -lOGLCompiler -lGenericCodeGen -lSPVRemapper -lSPIRV -lSPIRV-Tools-opt -lSPIRV-Tools -lpthread -lstdc++
+enabled libglslang && { check_lib libglslang glslang/Include/glslang_c_interface.h glslang_initialize_process \
+                            -lglslang -lMachineIndependent -lOSDependent -lHLSL -lOGLCompiler -lGenericCodeGen \
+                            -lSPVRemapper -lSPIRV -lSPIRV-Tools-opt -lSPIRV-Tools -lpthread -lstdc++ -lm ||
+                        require libglslang glslang/Include/glslang_c_interface.h glslang_initialize_process \
+                            -lglslang -lOSDependent -lHLSL -lOGLCompiler \
+                            -lSPVRemapper -lSPIRV -lSPIRV-Tools-opt -lSPIRV-Tools -lpthread -lstdc++ -lm; }
 enabled libgme            && { check_pkg_config libgme libgme gme/gme.h gme_new_emu ||
                                require libgme gme/gme.h gme_new_emu -lgme -lstdc++; }
 enabled libgsm            && { for gsm_hdr in "gsm.h" "gsm/gsm.h"; do