build system: try harder to detect w64devkit

We need to build the supplied PDCurses code when using w64devkit.
This was being detected by checking for the W64DEVKIT environment
variable, but this is only defined if w64devkit is started via
w64devkit.exe.

Set W64DEVKIT ourselves if HOSTCC targets the mingw32 platform.
This won't be the case when cross-compiling on Linux but will
for w64devkit and MSYS2 MINGW32/64.

The build won't work properly for MSYS2 MINGW32/64, but it doesn't
work when using the supplied curses library either.  'make menuconfig'
requires the use of MSYS2 MSYS, and HOSTCC there targets msys.

1 files changed, 11 insertions, 0 deletions

diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index e0d7e2190..ed07c4c62 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -2,6 +2,17 @@
 # Kernel configuration targets
 # These targets are used from top-level makefile
 
+# If w64devkit isn't run via w64devkit.exe W64DEVKIT won't be
+# defined.  If HOSTCC targets the mingw32 platform set W64DEVKIT.
+ifndef W64DEVKIT
+        host_target := $(shell $(HOSTCC) -v 2>&1 | grep ^Target:)
+        host_platform := $(lastword $(subst -, ,$(host_target)))
+        ifeq ($(host_platform),mingw32)
+                W64DEVKIT := 1
+                export W64DEVKIT
+        endif
+endif
+
 PHONY += oldconfig xconfig gconfig menuconfig config silentoldconfig update-po-config
 
 xconfig: $(obj)/qconf