ci: nswitch: do not rely on dkp-pacman at all

scripts/gha/build_nswitch_docker.sh

@@ -14,14 +14,28 @@ build_hlsdk()
   ./waf clean
 }
 
-echo "Downloading missing deps..."
+echo "Setting up environment..."
+
+# we can't actually download dkp-toolchain-vars even from here, so
+export PORTLIBS_ROOT=${DEVKITPRO}/portlibs
+export PATH=${DEVKITPRO}/tools/bin:${DEVKITPRO}/devkitA64/bin:$PATH
+export TOOL_PREFIX=aarch64-none-elf-
+export CC=${TOOL_PREFIX}gcc
+export CXX=${TOOL_PREFIX}g++
+export AR=${TOOL_PREFIX}gcc-ar
+export RANLIB=${TOOL_PREFIX}gcc-ranlib
+export PORTLIBS_PREFIX=${DEVKITPRO}/portlibs/switch
+export PATH=$PORTLIBS_PREFIX/bin:$PATH
+export ARCH="-march=armv8-a+crc+crypto -mtune=cortex-a57 -mtp=soft -fPIC -ftls-model=local-exec"
+export CFLAGS="${ARCH} -O2 -ffunction-sections -fdata-sections"
+export CXXFLAGS="${CFLAGS}"
+export CPPFLAGS="-D__SWITCH__ -I${PORTLIBS_PREFIX}/include -isystem ${DEVKITPRO}/libnx/include"
+export LDFLAGS="${ARCH} -L${PORTLIBS_PREFIX}/lib -L${DEVKITPRO}/libnx/lib"
+export LIBS="-lnx"
 
-dkp-pacman -S --noconfirm dkp-toolchain-vars || die
 # forgive me father, for I have sinned
 ln -s /usr/bin/python3 /usr/bin/python
 
-source $DEVKITPRO/switchvars.sh
-
 echo "Building libsolder..."
 
 make -C libsolder install || die