diff --git a/INSTALL b/INSTALL
index 33e43d9..400ce94 100644
--- a/INSTALL
+++ b/INSTALL
@@ -23,6 +23,8 @@ Prerequisites
 -------------
 - Imlib2 shared library and development headers. On a Debian or Ubuntu system
   they are provided by the packages libimlib2 and libimlib2-dev.
+  On Mac OS X you can use 'brew' to install Imlib2: brew install imlib2
+  (see http://mxcl.github.com/homebrew/)
 - Build tools, e.g. build-essential on a Debian (or Ubuntu) system.
 - To build a .deb package, you probably need the debhelper package.
 - To create an HTML version of the man page, you need rman.
diff --git a/Makefile b/Makefile
index a4b9126..0fb2dbc 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-CFLAGS := -D_FORTIFY_SOURCE=2 -Wall -W -Wextra -pedantic -Werror -pedantic-errors $(shell imlib2-config --cflags) -O6
+CFLAGS := -D_FORTIFY_SOURCE=2 -Wall -W -Wextra -pedantic -Werror -pedantic-errors $(shell imlib2-config --cflags) -O3
 LDLIBS := $(shell imlib2-config --libs)
 PREFIX := /usr/local
 BINDIR := $(PREFIX)/bin
diff --git a/defines.h b/defines.h
index dc23869..5789e7b 100644
--- a/defines.h
+++ b/defines.h
@@ -20,7 +20,7 @@
 #define SSOCR2_DEFINES_H
 
 /* version number */
-#define VERSION "2.13.2"
+#define VERSION "2.13.3"
 
 /* states */
 #define FIND_DARK 0
diff --git a/ssocr.c b/ssocr.c
index 210049b..1828288 100644
--- a/ssocr.c
+++ b/ssocr.c
@@ -1004,7 +1004,7 @@ int main(int argc, char **argv)
     int middle=0, quarter=0, three_quarters=0; /* scanlines */
     int d_height=0; /* height of digit */
     /* if digits[d].digit == D_ONE do nothing */
-    if((digits[d].digit == D_UNKNOWN)) {
+    if(digits[d].digit == D_UNKNOWN) {
       int third=1; /* in which third we are */
       int half;
       found_pixels=0; /* how many pixels are already found */