depends: default to using GCC tool wrappers (with GCC)

This improves support for LTO by using gcc wrappers for ar, nm, ranlib,
that correctly setup plugin arguments for LTO.

Other HOSTS are using clang.

depends/hosts/mingw32.mk

@@ -9,6 +9,10 @@ ifneq ($(LTO),)
 mingw32_CFLAGS += -flto
 mingw32_CXXFLAGS += -flto
 mingw32_LDFLAGS += -flto
+
+mingw32_AR = $(host_toolchain)gcc-ar
+mingw32_NM = $(host_toolchain)gcc-nm
+mingw32_RANLIB = $(host_toolchain)gcc-ranlib
 endif
 
 mingw32_release_CFLAGS=-O2