Use integer literals for builtin target_pointer_width fields

Also change target_pointer_width to pointer_width.

Preparation for a subsequent type change of
target_pointer_width to an integer together with a rename
to pointer_width.

On its own, this commit breaks the build. I don't like making
build-breaking commits, but in this instance I believe that it
makes review easier, as the "real" changes of this PR can be
seen much more easily.

Result of running:

find compiler/rustc_target/src/spec/ -type f -exec sed -i -e 's/target_pointer_width: "\(.*\)"\..*,/pointer_width: \1,/g' {} \;

Author: est31

compiler/rustc_target/src/spec/aarch64_apple_darwin.rs

@@ -17,7 +17,7 @@ pub fn target() -> Target {
     Target {
         llvm_target,
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:o-i64:64-i128:128-n32:64-S128".to_string(),
         arch: arch.to_string(),

compiler/rustc_target/src/spec/aarch64_apple_ios.rs

@@ -6,7 +6,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "arm64-apple-ios".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:o-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_apple_tvos.rs

@@ -6,7 +6,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "arm64-apple-tvos".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:o-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_fuchsia.rs

@@ -7,7 +7,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-fuchsia".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_linux_android.rs

@@ -12,7 +12,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-linux-android".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_pc_windows_msvc.rs

@@ -9,7 +9,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-pc-windows-msvc".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_unknown_cloudabi.rs

@@ -9,7 +9,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-unknown-cloudabi".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_unknown_freebsd.rs

@@ -7,7 +7,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-unknown-freebsd".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_unknown_hermit.rs

@@ -7,7 +7,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-unknown-hermit".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),
         arch: "aarch64".to_string(),

compiler/rustc_target/src/spec/aarch64_unknown_linux_gnu.rs

@@ -7,7 +7,7 @@ pub fn target() -> Target {
     Target {
         llvm_target: "aarch64-unknown-linux-gnu".to_string(),
         target_endian: "little".to_string(),
-        target_pointer_width: "64".to_string(),
+        pointer_width: 64,
         target_c_int_width: "32".to_string(),
         target_env: "gnu".to_string(),
         data_layout: "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128".to_string(),