PATCH: use sh function for set_cc_for_build

[Ben Elliston]

This change is a little complicated, so I would like to send the patch
to the list for review, please.  Paul Eggert agrees with me that it is
probably safe to start using POSIX shell functions in config.guess,
which means that we can now get rid of the huge and unwieldy
"set_cc_for_build" variable. I think you will agree that the new shell
function is much more readable, plus Shellcheck now has a hope of
comprehending it. ;-)

Look OK?

Ben


2018-07-08  Ben Elliston  <address@hidden>

        * config.guess: Replace monstrous 'set_cc_for_build' shell
        variable that is executed via eval with a POSIX shell function.
        * Makefile (shellcheck): Ignore SC2039 diagnostics ("In POSIX
        sh, RANDOM is undefined"). Fix suggested to Shellcheck maintainer.

diff --git a/config.guess b/config.guess
index 2b79f6d..20c381a 100755
--- a/config.guess
+++ b/config.guess
@@ -2,7 +2,7 @@
 # Attempt to guess a canonical system name.
 #   Copyright 1992-2018 Free Software Foundation, Inc.
 
-timestamp='2018-07-06'
+timestamp='2018-07-08'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -84,7 +84,11 @@ if test $# != 0; then
   exit 1
 fi
 
-trap 'exit 1' 1 2 15
+trap "rm -f \$tmpfiles 2>/dev/null; \
+      test -n \$tmp && rmdir \$tmp 2>/dev/null; exit 1" INT HUP PIPE TERM
+
+trap "exitcode=\$?; (rm -f \$tmpfiles 2>/dev/null; \
+      test -n \$tmp && rmdir \$tmp 2>/dev/null) && exit \$exitcode" EXIT
 
 # CC_FOR_BUILD -- compiler used by this script. Note that the use of a
 # compiler to aid in system detection is discouraged as it requires
@@ -96,30 +100,30 @@ trap 'exit 1' 1 2 15
 
 # Portable tmp directory creation inspired by the Autoconf team.
 
-set_cc_for_build='
-trap "exitcode=\$?; (rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null) && 
exit \$exitcode" 0 ;
-trap "rm -f \$tmpfiles 2>/dev/null; rmdir \$tmp 2>/dev/null; exit 1" 1 2 13 15 
;
-: ${TMPDIR=/tmp} ;
- { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n 
"$tmp" && test -d "$tmp" ; } ||
- { test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir $tmp 
2>/dev/null) ; } ||
- { tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir $tmp 2>/dev/null) && echo 
"Warning: creating insecure temp directory" >&2 ; } ||
- { echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; } 
;
-dummy=$tmp/dummy ;
-tmpfiles="$dummy.c $dummy.o $dummy.rel $dummy" ;
-case ${CC_FOR_BUILD-},${HOST_CC-},${CC-} in
- ,,)    echo "int x;" > "$dummy.c" ;
-       for c in cc gcc c89 c99 ; do
-         if ($c -c -o "$dummy.o" "$dummy.c") >/dev/null 2>&1 ; then
-            CC_FOR_BUILD="$c"; break ;
-         fi ;
-       done ;
-       if test x"$CC_FOR_BUILD" = x ; then
-         CC_FOR_BUILD=no_compiler_found ;
-       fi
-       ;;
- ,,*)   CC_FOR_BUILD=$CC ;;
- ,*,*)  CC_FOR_BUILD=$HOST_CC ;;
-esac ; set_cc_for_build= ;'
+set_cc_for_build() {
+    : "${TMPDIR=/tmp}"
+    { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n 
"$tmp" && test -d "$tmp" ; } ||
+       { test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir 
"$tmp" 2>/dev/null) ; } ||
+       { tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir "$tmp" 2>/dev/null) && echo 
"Warning: creating insecure temp directory" >&2 ; } ||
+       { echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 
1 ; }
+    dummy=$tmp/dummy
+    tmpfiles="$dummy.c $dummy.o $dummy.rel $dummy"
+    case ${CC_FOR_BUILD-},${HOST_CC-},${CC-} in
+       ,,)    echo "int x;" > "$dummy.c"
+              for driver in cc gcc c89 c99 ; do
+                  if ($driver -c -o "$dummy.o" "$dummy.c") >/dev/null 2>&1 ; 
then
+                      CC_FOR_BUILD="$driver"
+                      break
+                  fi
+              done
+              if test x"$CC_FOR_BUILD" = x ; then
+                  CC_FOR_BUILD=no_compiler_found
+              fi
+              ;;
+       ,,*)   CC_FOR_BUILD=$CC ;;
+       ,*,*)  CC_FOR_BUILD=$HOST_CC ;;
+    esac
+}
 
 # This is needed to find uname on a Pyramid OSx when run in the BSD universe.
 # (address@hidden 1994-08-24)
@@ -138,7 +142,7 @@ Linux|GNU|GNU/*)
        # We could probably try harder.
        LIBC=gnu
 
-       eval "$set_cc_for_build"
+       set_cc_for_build
        cat <<-EOF > "$dummy.c"
        #include <features.h>
        #if defined(__UCLIBC__)
@@ -199,7 +203,7 @@ case 
"$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
                os=netbsdelf
                ;;
            arm*|i386|m68k|ns32k|sh3*|sparc|vax)
-               eval "$set_cc_for_build"
+               set_cc_for_build
                if echo __ELF__ | $CC_FOR_BUILD -E - 2>/dev/null \
                        | grep -q __ELF__
                then
@@ -389,7 +393,7 @@ case 
"$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
        echo i386-pc-auroraux"$UNAME_RELEASE"
        exit ;;
     i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
-       eval "$set_cc_for_build"
+       set_cc_for_build
        SUN_ARCH=i386
        # If there is a compiler, see if it is configured for 64-bit objects.
        # Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
@@ -482,7 +486,7 @@ case 
"$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
        echo clipper-intergraph-clix"$UNAME_RELEASE"
        exit ;;
     mips:*:*:UMIPS | mips:*:*:RISCos)
-       eval "$set_cc_for_build"
+       set_cc_for_build
        sed 's/^        //' << EOF > "$dummy.c"
 #ifdef __cplusplus
 #include <stdio.h>  /* for printf() prototype */
@@ -579,7 +583,7 @@ EOF
        exit ;;
     *:AIX:2:3)
        if grep bos325 /usr/include/stdio.h >/dev/null 2>&1; then
-               eval "$set_cc_for_build"
+               set_cc_for_build
                sed 's/^                //' << EOF > "$dummy.c"
                #include <sys/systemcfg.h>
 
@@ -660,7 +664,7 @@ EOF
                    esac
                fi
                if [ "$HP_ARCH" = "" ]; then
-                   eval "$set_cc_for_build"
+                   set_cc_for_build
                    sed 's/^            //' << EOF > "$dummy.c"
 
                #define _HPUX_SOURCE
@@ -700,7 +704,7 @@ EOF
        esac
        if [ "$HP_ARCH" = hppa2.0w ]
        then
-           eval "$set_cc_for_build"
+           set_cc_for_build
 
            # hppa2.0w-hp-hpux* has a 64-bit kernel and a compiler generating
            # 32-bit code.  hppa64-hp-hpux* has the same kernel and a compiler
@@ -726,7 +730,7 @@ EOF
        echo ia64-hp-hpux"$HPUX_REV"
        exit ;;
     3050*:HI-UX:*:*)
-       eval "$set_cc_for_build"
+       set_cc_for_build
        sed 's/^        //' << EOF > "$dummy.c"
        #include <unistd.h>
        int
@@ -922,7 +926,7 @@ EOF
        echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
        exit ;;
     arm*:Linux:*:*)
-       eval "$set_cc_for_build"
+       set_cc_for_build
        if echo __ARM_EABI__ | $CC_FOR_BUILD -E - 2>/dev/null \
            | grep -q __ARM_EABI__
        then
@@ -971,7 +975,7 @@ EOF
        echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
        exit ;;
     mips:Linux:*:* | mips64:Linux:*:*)
-       eval "$set_cc_for_build"
+       set_cc_for_build
        sed 's/^        //' << EOF > "$dummy.c"
        #undef CPU
        #undef ${UNAME_MACHINE}
@@ -1285,7 +1289,7 @@ EOF
        exit ;;
     *:Darwin:*:*)
        UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
-       eval "$set_cc_for_build"
+       set_cc_for_build
        if test "$UNAME_PROCESSOR" = unknown ; then
            UNAME_PROCESSOR=powerpc
        fi
diff --git a/Makefile b/Makefile
index edab683..9744deb 100644
--- a/Makefile
+++ b/Makefile
@@ -17,4 +17,4 @@ check-sub:
        cd testsuite && sh config-sub.sh
 
 shellcheck:
-       shellcheck -e SC2006 -f gcc config.guess config.sub testsuite/*.sh
+       shellcheck -e SC2006,SC2039 -f gcc config.guess config.sub 
testsuite/*.sh

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