Rollup merge of #29876 - cardoe:i586-build-fix, r=alexcrichton

On distros that use i486 or i586 in their CHOST, Rust will fail to build
because it is not handling i486 or i586 like i686 is handled. This
changes the match to do work for all instances of i?86 instead of just
i686. The Yocto Project still uses i586 as a target.

Signed-off-by: Doug Goldstein <[email protected]>

Author: Manishearth

mk/platform.mk

@@ -14,7 +14,7 @@
 # would create a variable HOST_i686-darwin-macos with the value
 # i386.
 define DEF_HOST_VAR
-  HOST_$(1) = $(subst i686,i386,$(word 1,$(subst -, ,$(1))))
+  HOST_$(1) = $(patsubst i%86,i386,$(word 1,$(subst -, ,$(1))))
 endef
 $(foreach t,$(CFG_TARGET),$(eval $(call DEF_HOST_VAR,$(t))))
 $(foreach t,$(CFG_TARGET),$(info cfg: host for $(t) is $(HOST_$(t))))