https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91595
--- Comment #6 from Brecht Sanders <brechtsanders at users dot sourceforge.net> --- The patch for gcc/config/i386/t-cygming added a line: winnt-d.o: config/winnt-d.c I changed it to: winnt-d.o: config/i386/winnt-d.c Then I got one step further. Output is now: libtool: compile: /R/winlibs64_stage/gcc-10-20210320/build_mingw/./gcc/gdc -B/R/winlibs64_stage/gcc-10-20210320/build_mingw/./gcc/ -L/R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/x86_64-w64-mingw32/lib -L/R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/mingw/lib -isystem /R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/x86_64-w64-mingw32/include -isystem /R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/mingw/include -B/R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/x86_64-w64-mingw32/bin/ -B/R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/x86_64-w64-mingw32/lib/ -isystem /R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/x86_64-w64-mingw32/include -isystem /R/winlibs64_stage/inst_gcc-10-20210320/share/gcc/x86_64-w64-mingw32/sys-include --sysroot=/R/winlibs64_stage/gcc-10-20210320/build_mingw/mingw-w64 -DDLL_EXPORT -Wall -frelease -O2 -g -nostdinc -I ../../../../libphobos/libdruntime -I . -c ../../../../libphobos/libdruntime/core/demangle.d -fversion=Shared -o core/.libs/demangle.o r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:134:5: error: undefined identifier 'FILE' 134 | int fwprintf(FILE* stream, in wchar_t* format, ...); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:136:5: error: undefined identifier 'FILE' 136 | int fwscanf(FILE* stream, in wchar_t* format, ...); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:139:5: error: undefined identifier 'FILE' 139 | int vfwprintf(FILE* stream, in wchar_t* format, va_list arg); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:141:5: error: undefined identifier 'FILE' 141 | int vfwscanf(FILE* stream, in wchar_t* format, va_list arg); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:177:12: error: undefined identifier 'FILE' 177 | wint_t fgetwc(FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:179:12: error: undefined identifier 'FILE' 179 | wint_t fputwc(wchar_t c, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:183:10: error: undefined identifier 'FILE' 183 | wchar_t* fgetws(wchar_t* s, int n, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:185:10: error: undefined identifier 'FILE' 185 | int fputws(in wchar_t* s, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:195:12: error: undefined identifier 'FILE' 195 | wint_t getwc(FILE* stream) { return fgetwc(stream); } | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:197:12: error: undefined identifier 'FILE' 197 | wint_t putwc(wchar_t c, FILE* stream) { return fputwc(c, stream); } | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:204:12: error: undefined identifier 'FILE' 204 | wint_t ungetwc(wint_t c, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\wchar_.d:213:16: error: undefined identifier 'FILE' 213 | int fwide(FILE* stream, int mode); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1140:16: error: undefined identifier 'FILE' 1140 | @trusted FILE* tmpfile(); // No unsafe pointer manipulation. | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1145:7: error: undefined identifier 'FILE' 1145 | int fclose(FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1151:11: error: undefined identifier 'FILE' 1151 | int fflush(FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1155:7: error: undefined identifier 'FILE' 1155 | FILE* fopen(scope const char* filename, scope const char* mode); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1157:7: error: undefined identifier 'FILE' 1157 | FILE* freopen(scope const char* filename, scope const char* mode, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1157:7: error: undefined identifier 'FILE' 1157 | FILE* freopen(scope const char* filename, scope const char* mode, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1160:6: error: undefined identifier 'FILE' 1160 | void setbuf(FILE* stream, char* buf); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1162:6: error: undefined identifier 'FILE' 1162 | int setvbuf(FILE* stream, char* buf, int mode, size_t size); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1169:9: error: undefined identifier 'FILE' 1169 | int __mingw_fprintf(FILE* stream, scope const char* format, ...); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1174:9: error: undefined identifier 'FILE' 1174 | int __mingw_fscanf(FILE* stream, scope const char* format, ...); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1189:9: error: undefined identifier 'FILE' 1189 | int __mingw_vfprintf(FILE* stream, scope const char* format, va_list arg); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1194:9: error: undefined identifier 'FILE' 1194 | int __mingw_vfscanf(FILE* stream, scope const char* format, va_list arg); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1260:9: error: undefined identifier 'FILE' 1260 | int fgetc(FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1262:9: error: undefined identifier 'FILE' 1262 | int fputc(int c, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1266:7: error: undefined identifier 'FILE' 1266 | char* fgets(char* s, int n, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1268:7: error: undefined identifier 'FILE' 1268 | int fputs(scope const char* s, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1288:14: error: undefined identifier 'FILE' 1288 | @trusted int ungetc(int c, FILE* stream); // No unsafe pointer manipulation. | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1291:8: error: undefined identifier 'FILE' 1291 | size_t fread(scope void* ptr, size_t size, size_t nmemb, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1293:8: error: undefined identifier 'FILE' 1293 | size_t fwrite(scope const void* ptr, size_t size, size_t nmemb, FILE* stream); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1299:9: error: undefined identifier 'FILE' 1299 | int fgetpos(FILE* stream, scope fpos_t * pos); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1299:9: error: undefined identifier 'fpos_t' 1299 | int fgetpos(FILE* stream, scope fpos_t * pos); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1301:9: error: undefined identifier 'FILE' 1301 | int fsetpos(FILE* stream, scope const fpos_t* pos); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1301:9: error: undefined identifier 'fpos_t' 1301 | int fsetpos(FILE* stream, scope const fpos_t* pos); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1304:12: error: undefined identifier 'FILE' 1304 | int fseek(FILE* stream, c_long offset, int whence); | ^ r:\winlibs64_stage\gcc-10-20210320\libphobos\libdruntime\core\stdc\stdio.d:1306:12: error: undefined identifier 'FILE' 1306 | c_long ftell(FILE* stream); | ^ ../../../../libphobos/libdruntime/core/demangle.d:2622:16: error: module core.stdc.stdio import 'snprintf' not found, did you mean alias 'sprintf'? 2622 | import core.stdc.stdio : snprintf; | ^ make[4]: *** [Makefile:2280: core/demangle.lo] Error 1