Fix Windows cross-compilation from Unix

[musm]

There are several issues that cause the build to fail.

#39022 fixes a bug in the makefile and allows it to run (but this fix fails on Cygwin! so we can't use it)

$ make -j8
chmod a+x /home/mus/julia/julia.bat
0031:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0033:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0037:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0035:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0031:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0031:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0037:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0037:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0033:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0033:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0035:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0035:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0041:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0047:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0043:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0041:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0041:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0045:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0043:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0043:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0047:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0047:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0045:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0045:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
004f:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0051:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0051:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
004f:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0051:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
004f:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
0053:err:module:import_dll Library libstdc++-6.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0053:err:module:import_dll Library LLVM.dll (which is needed by L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe") not found
0053:err:module:LdrInitializeThunk Importing dlls for L"Z:\\home\\mus\\julia\\usr\\tools\\llvm-config.exe" failed, status c0000135
    FLISP src/julia_flisp.boot
002e:err:module:__wine_process_init failed to load L"Z:\\home\\mus\\julia\\src\\flisp\\flisp", error c000012f
make[1]: *** [Makefile:222: julia_flisp.boot] Error 47
make: *** [Makefile:43: julia_flisp.boot.inc.phony] Error 2

[vtjnash]

Please file a new issue with specific problems