auto merge of #10193 : osaut/rust/Fix_install, r=huonw

Fix missing parentheses coming from a previous substitution '$(PREFIX_ROOT)' to  '$(CFG_MANDIR' on 1c4a348

Author: bors

mk/install.mk

@@ -139,7 +139,7 @@ install-host: LIB_DESTIN_DIR=$(PHL)
 install-host: $(CSREQ$(ISTAGE)_T_$(CFG_BUILD_)_H_$(CFG_BUILD_))
 	$(Q)$(call MK_INSTALL_DIR,$(PREFIX_BIN))
 	$(Q)$(call MK_INSTALL_DIR,$(PREFIX_LIB))
-	$(Q)$(call MK_INSTALL_DIR,$(CFG_MANDIR/man1)
+	$(Q)$(call MK_INSTALL_DIR,$(CFG_MANDIR)/man1)
 	$(Q)$(call INSTALL,$(HB2),$(PHB),rustc$(X_$(CFG_BUILD)))
 	$(Q)$(call INSTALL,$(HB2),$(PHB),rustpkg$(X_$(CFG_BUILD)))
 	$(Q)$(call INSTALL,$(HB2),$(PHB),rustdoc$(X_$(CFG_BUILD)))
@@ -152,9 +152,9 @@ install-host: $(CSREQ$(ISTAGE)_T_$(CFG_BUILD_)_H_$(CFG_BUILD_))
 	$(Q)$(call INSTALL_LIB,$(LIBRUSTDOC_GLOB_$(CFG_BUILD)))
 	$(Q)$(call INSTALL,$(HL),$(PHL),$(CFG_RUNTIME_$(CFG_BUILD)))
 	$(Q)$(call INSTALL,$(HL),$(PHL),$(CFG_RUSTLLVM_$(CFG_BUILD)))
-	$(Q)$(call INSTALL,$(S)/man, $(CFG_MANDIR/man1,rustc.1)
-	$(Q)$(call INSTALL,$(S)/man, $(CFG_MANDIR/man1,rustdoc.1)
-	$(Q)$(call INSTALL,$(S)/man, $(CFG_MANDIR/man1,rustpkg.1)
+	$(Q)$(call INSTALL,$(S)/man, $(CFG_MANDIR)/man1,rustc.1)
+	$(Q)$(call INSTALL,$(S)/man, $(CFG_MANDIR)/man1,rustdoc.1)
+	$(Q)$(call INSTALL,$(S)/man, $(CFG_MANDIR)/man1,rustpkg.1)
 
 install-targets: $(INSTALL_TARGET_RULES)