Bug 497923 - [GTK] build.sh bugfixes and improvements

Shell script can't assign variable values in conditional constructs so
the double equals is redundant. Moreover it gives a syntax error on
older ash/dash or whatever HP-UX builder is using.

Change-Id: Ia1916b1ec16a4c1cafc54979336f39cc7065942e
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
diff --git a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/build.sh b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/build.sh
index 7da48d4..b2a4a8f 100755
--- a/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/build.sh
+++ b/bundles/org.eclipse.swt/Eclipse SWT PI/gtk/library/build.sh
@@ -46,7 +46,7 @@
 git reset --hard  #If existing binary was overwritten.
 "
 
-if [[ "$1" == "-h" || "$1" == "--help" ]]; then
+if [[ "$1" = "-h" || "$1" = "--help" ]]; then
 	echo "$HELP"
 	exit
 fi