[PATCH 3/4] Rewrite logic handling n `-`-separated components

[John Ericson]

The old logic was a bit hard to follow due to lots of sed and
unintuitive collapsing of cases. The code now works like this

 - 4 components is always parsed as
   CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM

 - 2 components is always parsed as
   CPU_TYPE-OPERATING_SYSTEM

 - 1 component is always parsed as
   CPU_TYPE

 - 3 components is ambiguous and parsed as either
   CPU_TYPE-MANUFACTURER-OPERATING_SYSTEM
   CPU_TYPE-KERNEL-OPERATING_SYSTEM

The old code differed semantically in that

 - The 4-case was awkwardly folded into the 3-case disambiguation

 - The "android-linux" ad-hoc fixdup did something different in the
   non-3 cases, but isn't intended to apply in those cases.
---
 ChangeLog  |  4 ++++
 config.sub | 43 ++++++++++++++++++++++++++++---------------
 2 files changed, 32 insertions(+), 15 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 600658c..5a9b2a3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2018-04-24  John Ericson  <address@hidden>
+
+       * config.sub: Properly recognise configs with 4 components.
+
 2018-04-24  John Ericson  <address@hidden>
 
        * config.sub (arm6m, armv[78][arm]): Recognise.
diff --git a/config.sub b/config.sub
index 18d0465..b0d1a74 100755
--- a/config.sub
+++ b/config.sub
@@ -110,33 +110,46 @@ case $# in
     exit 1;;
 esac
 
-# Separate what the user gave into CPU-COMPANY and OS or KERNEL-OS (if any).
-# Here we must recognize all the valid KERNEL-OS combinations.
-maybe_os=`echo "$1" | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\2/'`
-case $maybe_os in
+c1=`echo "$1" | sed 's/^\([^-]*\).*$/\1/'`
+c2=`echo "$1" | sed 's/^[^-]*-\([^-]*\).*$/\1/'`
+c3=`echo "$1" | sed 's/^[^-]*-[^-]*-\([^-]*\).*$/\1/'`
+c4=`echo "$1" | sed 's/^[^-]*-[^-]*-[^-]*-\([^-]*\).*$/\1/'`
+
+case $1 in
+  *-*-*-*)
+    basic_machine=$c1-$c2
+    os=-$c3-$c4
+    ;;
+  *-*-*)
+    # Ambiguous whether COMPANY is present, or skipped and KERNEL-OS is two 
parts
+    maybe_os=$c2-$c3
+    case $maybe_os in
       nto-qnx* | linux-gnu* | linux-android* | linux-dietlibc | linux-newlib* 
| \
       linux-musl* | linux-uclibc* | uclinux-uclibc* | uclinux-gnu* | 
kfreebsd*-gnu* | \
       knetbsd*-gnu* | netbsd*-gnu* | netbsd*-eabi* | \
       kopensolaris*-gnu* | cloudabi*-eabi* | \
       storm-chaos* | os2-emx* | rtmk-nova*)
+        basic_machine=$c1
         os=-$maybe_os
-        basic_machine=`echo "$1" | sed 's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`
         ;;
       android-linux)
+        basic_machine=$c1-unknown
         os=-linux-android
-        basic_machine=`echo "$1" | sed 
's/^\(.*\)-\([^-]*-[^-]*\)$/\1/'`-unknown
         ;;
       *)
-        basic_machine=`echo "$1" | sed 's/-[^-]*$//'`
-        case $1 in
-          *-*)
-            os=`echo "$1" | sed 's/.*-/-/'`
-            ;;
-          *)
-            os=
-            ;;
-        esac
+        basic_machine=$c1-$c2
+        os=-$c3
         ;;
+    esac
+    ;;
+  *-*)
+    basic_machine=$c1
+    os=-$c2
+    ;;
+  *)
+    basic_machine=$1
+    os=
+    ;;
 esac
 
 ### Let's recognize common machines as not being operating systems so
-- 
2.16.2