configure: add options so that shared build is possible on MINGW

Co-authored-by: Naveen M K <[email protected]>

configure.ac

@@ -1520,6 +1520,11 @@ if test $enable_shared = "yes"; then
           LDLIBRARY='libpython$(LDVERSION).dll.a'
           DLLLIBRARY='libpython$(LDVERSION).dll'
           ;;
+    MINGW*)
+          LDLIBRARY='libpython$(LDVERSION).dll.a'
+          DLLLIBRARY='libpython$(LDVERSION).dll'
+          BLDLIBRARY='-L. -lpython$(LDVERSION)'
+          ;;
     SunOS*)
 	  LDLIBRARY='libpython$(LDVERSION).so'
 	  BLDLIBRARY='-Wl,-R,$(LIBDIR) -L. -lpython$(LDVERSION)'
@@ -1570,6 +1575,9 @@ else # shared is disabled
           BLDLIBRARY='$(LIBRARY)'
           LDLIBRARY='libpython$(LDVERSION).dll.a'
           ;;
+    MINGW*)
+          LDLIBRARY='libpython$(LDVERSION).a'
+          ;;
   esac
 fi
 
@@ -3332,6 +3340,10 @@ then
 	CYGWIN*)
 		LDSHARED="gcc -shared -Wl,--enable-auto-image-base"
 		LDCXXSHARED="g++ -shared -Wl,--enable-auto-image-base";;
+  MINGW*)
+    LDSHARED='$(CC) -shared -Wl,--enable-auto-image-base'
+    LDCXXSHARED='$(CXX) -shared -Wl,--enable-auto-image-base'
+    ;;
 	*)	LDSHARED="ld";;
 	esac
 fi
@@ -6491,7 +6503,8 @@ case $host in
     dnl "errmap.h" from $srcdir/PC.
     dnl Note we cannot use BASECPPFLAGS as autogenerated pyconfig.h
     dnl has to be before customized located in ../PC.
-    CPPFLAGS="-I\$(srcdir)/PC $CPPFLAGS"
+    dnl (-I. at end is workaround for setup.py logic)
+    CPPFLAGS="-I\$(srcdir)/PC $CPPFLAGS -I."
     ;;
 esac