depends: remove ENV unsetting for darwin

Now that we use the native compiler, and have fixed Qt, and these vars
are unset it Guix, we can remove the unsetting from our compiler command
here.

Fixes #21552.

Author: fanquake

depends/hosts/darwin.mk

@@ -50,17 +50,11 @@ darwin_STRIP=$(shell $(SHELL) $(.SHELLFLAGS) "command -v llvm-strip")
 #         Disable adhoc codesigning (for now) when using LLVM tooling, to avoid
 #         non-determinism issues with the Identifier field.
 
-darwin_CC=env -u C_INCLUDE_PATH -u CPLUS_INCLUDE_PATH \
-              -u OBJC_INCLUDE_PATH -u OBJCPLUS_INCLUDE_PATH -u CPATH \
-              -u LIBRARY_PATH \
-              $(clang_prog) --target=$(host) \
+darwin_CC=$(clang_prog) --target=$(host) \
               -isysroot$(OSX_SDK) -nostdlibinc \
               -iwithsysroot/usr/include -iframeworkwithsysroot/System/Library/Frameworks
 
-darwin_CXX=env -u C_INCLUDE_PATH -u CPLUS_INCLUDE_PATH \
-               -u OBJC_INCLUDE_PATH -u OBJCPLUS_INCLUDE_PATH -u CPATH \
-               -u LIBRARY_PATH \
-               $(clangxx_prog) --target=$(host) \
+darwin_CXX=$(clangxx_prog) --target=$(host) \
                -isysroot$(OSX_SDK) -nostdlibinc \
                -iwithsysroot/usr/include/c++/v1 \
                -iwithsysroot/usr/include -iframeworkwithsysroot/System/Library/Frameworks