cairo: remove sed -i

extra/cairo/build

@@ -1,11 +1,15 @@
 #!/bin/sh -e
 
 # Disable building 'cairo-sphinx'.
-sed -i "s/BUILD_SPHINX_TRUE=/BUILD_SPHINX_TRUE='#'/"   configure
-sed -i "s/BUILD_SPHINX_FALSE='#'/BUILD_SPHINX_FALSE=/" configure
+sed -e "s/\(BUILD_SPHINX_TRUE=\)/\1'#'/" \
+    -e "s/\(BUILD_SPHINX_FALSE=\)'#'/\1=/" \
+    configure > _
+mv -f _ configure
+chmod +x configure
 
 # Disable building tests.
-sed -i 's/test perf//g' Makefile.in
+sed 's/test perf//g' Makefile.in > _
+mv -f _ Makefile.in
 
 ./configure \
     --prefix=/usr \