Description:

The st package doesn't copy config.h correctly when building the package, meaning no changes to the file take effect.

Additional info:
Bug occurs with st 0.6-3.

Here is a PKGBUILD which copies config.h correctly in prepare():

pkgname=st
pkgver=0.6
pkgrel=4
pkgdesc='A simple virtual terminal emulator for X.'
arch=('i686' 'x86_64')
license=('MIT')
depends=('libxft' 'libxext' 'xorg-fonts-misc')
makedepends=('ncurses')
url="http://st.suckless.org"
source=(http://dl.suckless.org/st/$pkgname-$pkgver.tar.gz
config.h)
md5sums=('1a926f450b4eacb7e2f5ac5b8ffea7c8'
'06f5d56f754a918916d6c92df75e6d11')

prepare() {
cd $srcdir/$pkgname-$pkgver
# skip terminfo which conflicts with nsurses
sed -i '/\@tic /d' Makefile
cp $srcdir/config.h config.h
}

build() {
cd $srcdir/$pkgname-$pkgver
cp $srcdir/config.h config.h
make X11INC=/usr/include/X11 X11LIB=/usr/lib/X11
}

package() {
cd $srcdir/$pkgname-$pkgver
make PREFIX=/usr DESTDIR="$pkgdir" TERMINFO="$pkgdir/usr/share/terminfo" install
install -Dm644 LICENSE "$pkgdir/usr/share/licenses/$pkgname/LICENSE"
install -Dm644 README "$pkgdir/usr/share/doc/$pkgname/README"
}

Steps to reproduce:

1. Fetch community/st using abs
2. Build and install st with e.g. makepkg -si
3. Modify config.h
4. Rebuild and reinstall st with e.g. makepkg -efi