Resolve $PREFIX to an absolute path at the start of shell scripts

This fixes building/installing into a relative path.

build-compiler-rt.sh

@@ -19,6 +19,9 @@ if [ -z "$PREFIX" ]; then
     echo $0 [--build-sanitizers] dest
     exit 1
 fi
+
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
 export PATH=$PREFIX/bin:$PATH
 
 : ${CORES:=$(nproc 2>/dev/null)}

build-libcxx.sh

@@ -23,6 +23,10 @@ if [ -z "$PREFIX" ]; then
     echo $0 [--disable-shared] [--disable-static] dest
     exit 1
 fi
+
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
+
 export PATH=$PREFIX/bin:$PATH
 
 : ${CORES:=$(nproc 2>/dev/null)}

build-libssp.sh

@@ -7,6 +7,8 @@ if [ $# -lt 1 ]; then
     exit 1
 fi
 PREFIX="$1"
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
 export PATH=$PREFIX/bin:$PATH
 
 : ${CORES:=$(nproc 2>/dev/null)}

build-llvm.sh

@@ -22,6 +22,9 @@ if [ -z "$PREFIX" ]; then
     exit 1
 fi
 
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
+
 : ${CORES:=$(nproc 2>/dev/null)}
 : ${CORES:=$(sysctl -n hw.ncpu 2>/dev/null)}
 : ${CORES:=4}

build-mingw-w64-libraries.sh

@@ -7,6 +7,8 @@ if [ $# -lt 1 ]; then
     exit 1
 fi
 PREFIX="$1"
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
 export PATH=$PREFIX/bin:$PATH
 
 : ${CORES:=$(nproc 2>/dev/null)}

build-mingw-w64.sh

@@ -14,6 +14,10 @@ if [ -z "$PREFIX" ]; then
     echo $0 [--skip-include-triplet-prefix] dest
     exit 1
 fi
+
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
+
 if [ -z "$HOST" ]; then
     # The newly built toolchain isn't crosscompiled; add it to the path.
     export PATH=$PREFIX/bin:$PATH

install-wrappers.sh

@@ -7,6 +7,8 @@ if [ $# -lt 1 ]; then
     exit 1
 fi
 PREFIX="$1"
+mkdir -p "$PREFIX"
+PREFIX="$(cd "$PREFIX" && pwd)"
 
 : ${ARCHS:=${TOOLCHAIN_ARCHS-i686 x86_64 armv7 aarch64}}