Ignore LLVM-dependent run-make tests on Windows

This should solve the PATH issue, and we don't need to test cross-lang
LTO working on all OS-es.

Author: Mark-Simulacrum

src/test/run-make-fulldeps/cross-lang-lto-upstream-rlibs/Makefile

@@ -1,6 +1,9 @@
-
 -include ../tools.mk
 
+# ignore windows due to libLLVM being present in PATH and the PATH and library path being the same
+# (so fixing it is harder). See #57765 for context
+ifndef IS_WINDOWS
+
 # This test makes sure that we don't loose upstream object files when compiling
 # staticlibs with -Zcross-lang-lto
 
@@ -21,3 +24,9 @@ all: staticlib.rs upstream.rs
 	$(RUSTC) staticlib.rs -Z cross-lang-lto -Ccodegen-units=1 -Clto=thin -L. -o $(TMPDIR)/staticlib.a
 	(cd $(TMPDIR); $(LD_LIB_PATH_ENVVAR)=$(REAL_LD_LIBRARY_PATH) llvm-ar x ./staticlib.a)
 	ls $(TMPDIR)/upstream.*.rcgu.o
+
+else
+
+all:
+
+endif

src/test/run-make-fulldeps/cross-lang-lto/Makefile

@@ -1,6 +1,10 @@
 
 -include ../tools.mk
 
+# ignore windows due to libLLVM being present in PATH and the PATH and library path being the same
+# (so fixing it is harder). See #57765 for context
+ifndef IS_WINDOWS
+
 # This test makes sure that the object files we generate are actually
 # LLVM bitcode files (as used by linker LTO plugins) when compiling with
 # -Z cross-lang-lto.
@@ -45,3 +49,9 @@ rdylib: lib.rs
 exe: lib.rs
 	$(BUILD_EXE) -o $(TMPDIR)/exe.o
 	$(call ASSERT_IS_BITCODE_OBJ, $(TMPDIR)/exe.o)
+
+else
+
+all:
+
+endif