Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

build-scripts/emscripten-buildbot.sh

@@ -0,0 +1,72 @@
+#!/bin/bash
+
+SDKDIR="/emsdk_portable"
+ENVSCRIPT="$SDKDIR/emsdk_env.sh"
+if [ ! -f "$ENVSCRIPT" ]; then
+   echo "ERROR: This script expects the Emscripten SDK to be in '$SDKDIR'." 1>&2
+   exit 1
+fi
+
+TARBALL="$1"
+if [ -z $1 ]; then
+    TARBALL=sdl-emscripten.tar.xz
+fi
+
+cd `dirname "$0"`
+cd ..
+SDLBASE=`pwd`
+
+if [ -z "$MAKE" ]; then
+    OSTYPE=`uname -s`
+    if [ "$OSTYPE" == "Linux" ]; then
+        NCPU=`cat /proc/cpuinfo |grep vendor_id |wc -l`
+        let NCPU=$NCPU+1
+    elif [ "$OSTYPE" = "Darwin" ]; then
+        NCPU=`sysctl -n hw.ncpu`
+    elif [ "$OSTYPE" = "SunOS" ]; then
+        NCPU=`/usr/sbin/psrinfo |wc -l |sed -e 's/^ *//g;s/ *$//g'`
+    else
+        NCPU=1
+    fi
+
+    if [ -z "$NCPU" ]; then
+        NCPU=1
+    elif [ "$NCPU" = "0" ]; then
+        NCPU=1
+    fi
+
+    MAKE="make -j$NCPU"
+fi
+
+echo "\$MAKE is '$MAKE'"
+
+echo "Setting up Emscripten SDK environment..."
+source "$ENVSCRIPT"
+
+echo "Setting up..."
+set -x
+cd "$SDLBASE"
+rm -rf buildbot
+mkdir buildbot
+pushd buildbot
+
+echo "Configuring..."
+emconfigure ../configure --host=asmjs-unknown-emscripten --disable-assembly --disable-threads --enable-cpuinfo=false CFLAGS="-O2 -Wno-warn-absolute-paths -Wdeclaration-after-statement -Werror=declaration-after-statement" --prefix="$PWD/emscripten-sdl2-installed"
+
+echo "Building..."
+emmake $MAKE
+
+echo "Moving things around..."
+emmake $MAKE install
+# Fix up a few things to a real install path
+perl -w -pi -e "s#$PWD/emscripten-sdl2-installed#/usr/local#g;" ./emscripten-sdl2-installed/lib/libSDL2.la ./emscripten-sdl2-installed/lib/pkgconfig/sdl2.pc ./emscripten-sdl2-installed/bin/sdl2-config
+mkdir -p ./usr
+mv ./emscripten-sdl2-installed ./usr/local
+popd
+tar -cJvvf $TARBALL -C buildbot usr
+rm -rf buildbot
+
+exit 0
+
+# end of emscripten-buildbot.sh ...
+