Merge branch 'unset-cc-and-cxx-in-prefix-build' into 'master'

Two fixes for the MacOS prefix build

Closes #1372

See merge request !1331

bootstrap.sh

@@ -109,6 +109,7 @@ osx_macports()
     install_macports_pkg "ninja"
     install_macports_pkg "po4a"
     install_macports_pkg "findutils"
+    install_macports_pkg "texinfo"
 }
 
 ###############################################################################
@@ -144,6 +145,7 @@ osx_homebrew()
     install_brew_pkg "po4a"
     install_brew_pkg "macfuse"
     install_brew_pkg "findutils"
+    install_brew_pkg "texinfo"
 
     install_brew_pkg "redox-os/gcc_cross_compilers/x86_64-elf-gcc" "x86_64-elf-gcc"
 }

mk/prefix.mk

@@ -7,6 +7,9 @@ export PREFIX_RUSTFLAGS=-L $(ROOT)/$(PREFIX_INSTALL)/$(TARGET)/lib
 export RUSTUP_TOOLCHAIN=$(ROOT)/$(PREFIX_INSTALL)
 export REDOXER_TOOLCHAIN=$(RUSTUP_TOOLCHAIN)
 
+export CC=
+export CXX=
+
 prefix: $(PREFIX_INSTALL)
 
 PREFIX_STRIP=\