[gparted] Check for pkexec >= 0.102 which supports execution of X11 apps (#776437)

[Curtis Gedak <gedakc src gnome org>]

commit 11c251293e6fd156b57905409efc5464bd85b202
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Sat Aug 12 11:52:30 2017 +0100

    Check for pkexec >= 0.102 which supports execution of X11 apps (#776437)
    
    On CentOS 6 with polkit version 0.96 pkexec fails to execute gparted
    shell wrapper as root like this:
    
        $ env | grep DISPLAY
        DISPLAY=:0.0
        $ sh -x /usr/local/bin/gparted
        ...
        + pkexec /usr/local/bin/gparted
        (gpartedbin:8011): Gtk-WARNING **: cannot open display:
    
    This is because polkit didn't support setting the DISPLAY environment
    variable to allow execution of X11 applications until the introduction
    of the allow_gui annotation by this commit in polkit 0.102:
    
        https://cgit.freedesktop.org/polkit/commit/?id=7850d27017fed1834268a852350ae85381fbb110
        Bug 38769 - pkexec: Support running X11 apps
    
    Make configure only use pkexec version 0.102 or higher as the privilege
    escalation program.  Otherwise configure falls back to checking for the
    other privilege escalation programs as it did before.
    
    Bug 776437 - GParted fails to run as root under Wayland

 README       |   11 +++++++----
 configure.ac |   33 +++++++++++++++++++++++++--------
 2 files changed, 32 insertions(+), 12 deletions(-)
---
diff --git a/README b/README
index 46eb244..216e326 100644
--- a/README
+++ b/README
@@ -165,13 +165,16 @@ c. Installing polkit's Action File
    graphical privilege escalation program examine the output from
    ./configure.  These lines report that pkexec is being used:
 
-      checking for pkexec... pkexec
+      checking for pkexec >= 0.102... 0.112 found
       checking how to run pkexec... pkexec --disable-internal-agent
 
-   Where as this line of ./configure output reports that pkexec is not
-   being used:
+   Where as either of these lines of ./configure output report that
+   pkexec is not being used because either it was too old a version or
+   it was not found:
 
-      checking for pkexec... no
+      checking for pkexec >= 0.102... 0.96 found
+
+      checking for pkexec >= 0.102... not found
 
    When GParted is configured with prefix /usr (using command
    ./configure --prefix=/usr) then make install will automatically
diff --git a/configure.ac b/configure.ac
index 9fcd741..3e77657 100644
--- a/configure.ac
+++ b/configure.ac
@@ -23,16 +23,33 @@ PKG_CHECK_EXISTS
 dnl======================
 dnl Find graphical privilege escalation program
 dnl======================
-AC_CHECK_PROGS([GKSUPROG], [pkexec gksudo gksu kdesudo "xdg-su -c"], [])
-
+dnl Check for pkexec >= 0.102 for it's ability to run X11 apps and
+dnl whether the --disable-internal-agent option is available.
 AM_CONDITIONAL([INSTALL_POLKIT_ACTIONS], false)
-if test "x$GKSUPROG" = 'xpkexec'; then
-       AC_MSG_CHECKING([how to run pkexec])
-       if pkexec --help 2>&1 | grep -q -- --disable-internal-agent; then
-               GKSUPROG="$GKSUPROG --disable-internal-agent"
+PKEXEC_REQUIRED_VERSION='0.102'
+AC_MSG_CHECKING([for pkexec >= $PKEXEC_REQUIRED_VERSION])
+PKEXEC_REQUIRED_INT=`echo "$PKEXEC_REQUIRED_VERSION" | $AWK -F. '{print $1 * 10000 + $2}'`
+PKEXEC_VERSION_OUTPUT=`pkexec --version 2> /dev/null` ||
+       AC_MSG_RESULT([not found])
+if test "x$PKEXEC_VERSION_OUTPUT" != 'x'; then
+       PKEXEC_FOUND_VERSION=`echo "$PKEXEC_VERSION_OUTPUT" | head -1 | cut -d' ' -f3`
+       PKEXEC_FOUND_INT=`echo "$PKEXEC_FOUND_VERSION" | $AWK -F. '{print $1 * 10000 + $2}'`
+       AC_MSG_RESULT([$PKEXEC_FOUND_VERSION found])
+       if test "$PKEXEC_FOUND_INT" -ge "$PKEXEC_REQUIRED_INT"; then
+               GKSUPROG='pkexec'
+               AC_MSG_CHECKING([how to run pkexec])
+               if pkexec --help 2>&1 | grep -q -- --disable-internal-agent; then
+                       GKSUPROG="$GKSUPROG --disable-internal-agent"
+               fi
+               AC_MSG_RESULT([$GKSUPROG])
+               AC_SUBST([GKSUPROG])
+               AM_CONDITIONAL([INSTALL_POLKIT_ACTIONS], true)
        fi
-       AC_MSG_RESULT([$GKSUPROG])
-       AM_CONDITIONAL([INSTALL_POLKIT_ACTIONS], true)
+fi
+
+dnl Check for alternative graphical privilege escalation programs.
+if test "x$GKSUPROG" = 'x'; then
+       AC_CHECK_PROGS([GKSUPROG], [gksudo gksu kdesudo "xdg-su -c"], [])
 fi