diff --git a/ANNOUNCE b/ANNOUNCE
index 755a1d77e..9533578d2 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -27,6 +27,7 @@ Other information:
 Changes since the last public release (1.4.2):
 
 version 1.4.3beta01 [May 14, 2010]
+  Added missing quotation marks in the aix block of configure.ac
 
 Send comments/corrections/commendations to glennrp at users.sourceforge.net
 or to png-mng-implement at lists.sf.net (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 65bb6c089..0b263feaa 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2577,6 +2577,7 @@ version 1.4.2rc06 [May 3, 2010]
 version 1.4.2 [May 6, 2010]
 
 version 1.4.3beta01 [May 14, 2010]
+  Added missing quotation marks in the aix block of configure.ac
 
 Send comments/corrections/commendations to glennrp at users.sourceforge.net
 or to png-mng-implement at lists.sf.net (subscription required; visit
diff --git a/configure b/configure
index 9f658c362..960658f89 100755
--- a/configure
+++ b/configure
@@ -11417,7 +11417,7 @@ fi
 
 case $host_os in
   aix*)
-   LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG -D_ALL_SOURCE;;
+   LIBPNG_DEFINES="-DPNG_CONFIGURE_LIBPNG -D_ALL_SOURCE";;
   *)
    LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG;;
 esac
diff --git a/configure.ac b/configure.ac
index 85e32debe..053372f22 100644
--- a/configure.ac
+++ b/configure.ac
@@ -61,7 +61,7 @@ AC_CHECK_LIB(z, zlibVersion, , AC_ERROR([zlib not installed]))
 
 case $host_os in
   aix*)
-   LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG -D_ALL_SOURCE;;
+   LIBPNG_DEFINES="-DPNG_CONFIGURE_LIBPNG -D_ALL_SOURCE";;
   *)
    LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG;;
 esac