[Driver][test] Add -fuse-ld= option tests for NetBSD

[MaskRay]

I am unsure it is useful to add a test for all OSxfuse_ld_value combinations, especially for an ELF OS like NetBSD which shares many characteristics with other ELF OSes. It will be overwhelming.
The option may be better added in a netbsd specific file.

[fcambus]

In D128757#3616795, @MaskRay wrote:

I am unsure it is useful to add a test for all OSxfuse_ld_value combinations, especially for an ELF OS like NetBSD which shares many characteristics with other ELF OSes. It will be overwhelming.
The option may be better added in a netbsd specific file.

I noticed there is a fuse-ld-windows.c file with some tests, so would putting NetBSD ones in a new fuse-ld-netbsd.c file make sense?

Either way, I don't have any strong opinion on this. I can also drop the revision if those tests do not seem useful.

[MaskRay]

Windows is very different from all other OSes. Having a fuse-ld-windows.c may be fine. Again, NetBSD shares many characteristics with other OSes and having a -fuse-ld=lld
test for all ~10 ELF OSes Clang supports seems too much.

[fcambus]

Agreed, that makes sense. Sorry for the noise.

clang/test/Driver/fuse-ld.c

 
 // RUN: %clang %s -### -fuse-ld=plib \
 // RUN:     --sysroot=%S/Inputs/basic_freebsd_tree \
 // RUN:     -target x86_64-unknown-freebsd \
 // RUN:     -B%S/Inputs/basic_freebsd_tree/usr/bin 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-PLIB
 // CHECK-FREEBSD-PLIB: error: invalid linker name
 
+// RUN: %clang %s -### \
+// RUN:     -target x86_64-unknown-netbsd 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-NETBSD-LD
+// CHECK-NETBSD-LD: ld
+
+// RUN: %clang %s -### -fuse-ld=bfd \
+// RUN:     --sysroot=%S/Inputs/basic_netbsd_tree \
+// RUN:     -target x86_64-unknown-netbsd \
+// RUN:     -B%S/Inputs/basic_netbsd_tree/usr/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-NETBSD-BFD
+// CHECK-NETBSD-BFD: Inputs/basic_netbsd_tree/usr/bin{{/|\\+}}ld.bfd
+
+// RUN: %clang %s -### -fuse-ld=gold \
+// RUN:     --sysroot=%S/Inputs/basic_netbsd_tree \
+// RUN:     -target x86_64-unknown-netbsd \
+// RUN:     -B%S/Inputs/basic_netbsd_tree/usr/bin 2>&1 \
+// RUN:   | FileCheck %s -check-prefix=CHECK-NETBSD-GOLD
+// CHECK-NETBSD-GOLD: Inputs/basic_netbsd_tree/usr/bin{{/|\\+}}ld.gold
+
 // RUN: %clang %s -### -fuse-ld=ld \
 // RUN:     -target arm-linux-androideabi \
 // RUN:     -B%S/Inputs/basic_android_tree/bin/arm-linux-androideabi- 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-ANDROID-ARM-LD
 // CHECK-ANDROID-ARM-LD: Inputs/basic_android_tree/bin{{/|\\+}}arm-linux-androideabi-ld
 
 // RUN: %clang %s -### -fuse-ld=bfd \
 // RUN:     -target arm-linux-androideabi \