Search for mingw-$prog too.

configure

@@ -12711,7 +12711,7 @@ echo "${ECHO_T}$ac_cv_c_dll_macho" >&6
 
     if test "$cross_compiling" = "no"
     then
-      for ac_prog in i586-mingw32msvc-gcc i386-mingw32-gcc
+      for ac_prog in i586-mingw32msvc-gcc i386-mingw32-gcc mingw-gcc
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -12752,7 +12752,7 @@ fi
 done
 test -n "$CROSSCC" || CROSSCC="false"
 
-      for ac_prog in i586-mingw32msvc-dlltool i386-mingw32-dlltool
+      for ac_prog in i586-mingw32msvc-dlltool i386-mingw32-dlltool mingw-dlltool
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -12793,7 +12793,7 @@ fi
 done
 test -n "$DLLTOOL" || DLLTOOL="false"
 
-      for ac_prog in i586-mingw32msvc-windres i386-mingw32-windres
+      for ac_prog in i586-mingw32msvc-windres i386-mingw32-windres mingw-windres
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2

configure.ac

@@ -942,9 +942,9 @@ case $host_os in
     AC_SUBST(CROSSTEST,"")
     if test "$cross_compiling" = "no"
     then
-      AC_CHECK_PROGS(CROSSCC,i586-mingw32msvc-gcc i386-mingw32-gcc,false)
-      AC_CHECK_PROGS(DLLTOOL,i586-mingw32msvc-dlltool i386-mingw32-dlltool,false)
-      AC_CHECK_PROGS(CROSSWINDRES,i586-mingw32msvc-windres i386-mingw32-windres,false)
+      AC_CHECK_PROGS(CROSSCC,i586-mingw32msvc-gcc i386-mingw32-gcc mingw-gcc,false)
+      AC_CHECK_PROGS(DLLTOOL,i586-mingw32msvc-dlltool i386-mingw32-dlltool mingw-dlltool,false)
+      AC_CHECK_PROGS(CROSSWINDRES,i586-mingw32msvc-windres i386-mingw32-windres mingw-windres,false)
       if test "$CROSSCC" != "false"; then CROSSTEST="\$(CROSSTEST)"; fi
     fi
     ;;