Build toolchain with PIC

This will be required for eld.

Some of the cross-built toolchains fail, because a limitation with zig's
use of libclang.  They fail with `error: unsupported linker arg: -Bsymbolic-functions`.
Bypassing that failure by disabling the clang-shlib results in a link
failure (see below).  So for now we'll just use non-PIC for the
toolchain targets that fail.

```
LLD Link... ld.lld: error: attempted static link of dynamic object lib/libclang.so.20.1.0-rc3
```

Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>

build-toolchain.sh

@@ -10,6 +10,7 @@ set -x
 
 build_llvm_clang_cross() {
 	triple=${1}
+	pic=${2-OFF}
 	cd ${BASE}
 
 	EXTRA=""
@@ -36,7 +37,7 @@ build_llvm_clang_cross() {
 		-DLLVM_TOOL_DSYMUTIL_BUILD:BOOL=OFF \
 		-DLLVM_INCLUDE_TESTS:BOOL=OFF \
 		-DLLVM_INCLUDE_EXAMPLES:BOOL=OFF \
-		-DLLVM_ENABLE_PIC:BOOL=OFF \
+		-DLLVM_ENABLE_PIC:BOOL=${pic} \
 		-DLLVM_NATIVE_TOOL_DIR=${PWD}/obj_llvm/bin \
 		-DCMAKE_BUILD_WITH_INSTALL_RPATH:BOOL=ON \
 		-DCMAKE_CROSSCOMPILING:BOOL=ON \
@@ -69,7 +70,7 @@ build_llvm_clang() {
 		-DLLVM_ENABLE_LIBCXX:BOOL=ON \
 		-DLLVM_ENABLE_TERMINFO:BOOL=OFF \
 		-DLLVM_ENABLE_ASSERTIONS:BOOL=ON \
-		-DLLVM_ENABLE_PIC:BOOL=OFF \
+		-DLLVM_ENABLE_PIC:BOOL=ON \
 		-C ./llvm-project/clang/cmake/caches/hexagon-unknown-linux-musl-clang.cmake \
 		-C ./llvm-project/clang/cmake/caches/hexagon-unknown-linux-musl-clang-cross.cmake \
 		-B ./obj_llvm \
@@ -322,12 +323,17 @@ python3.8 --version
 
 build_llvm_clang
 
-CROSS_TRIPLES="aarch64-windows-gnu x86_64-windows-gnu x86_64-linux-musl aarch64-linux-gnu aarch64-macos"
-CROSS_TRIPLES="aarch64-windows-gnu x86_64-windows-gnu x86_64-linux-musl aarch64-linux-gnu"
+#CROSS_TRIPLES="x86_64-linux-musl aarch64-linux-gnu aarch64-macos"
+CROSS_TRIPLES="x86_64-linux-musl aarch64-linux-musl"
+CROSS_TRIPLES_PIC="aarch64-windows-gnu x86_64-windows-gnu"
 for t in ${CROSS_TRIPLES}
 do
 	build_llvm_clang_cross ${t}
 done
+for t in ${CROSS_TRIPLES_PIC}
+do
+	build_llvm_clang_cross ${t} ON
+done
 ccache --show-stats
 config_kernel
 build_kernel_headers