link.exe: don't embed full path to PDB file in binary.

tests/run-make/pdb-alt-path/Makefile

@@ -0,0 +1,20 @@
+include ../tools.mk
+
+# only-windows-msvc
+
+all:
+	# Test that we don't have the full path to the PDB file in the binary
+	$(RUSTC) main.rs -g --crate-name my_crate_name --crate-type bin
+	$(CGREP) "my_crate_name.pdb" < $(TMPDIR)/my_crate_name.exe
+	$(CGREP) -v "\\my_crate_name.pdb" < $(TMPDIR)/my_crate_name.exe
+
+	# Test that backtraces still can find debuginfo by checking that they contain symbol names and
+	# source locations.
+	RUST_BACKTRACE="full" $(TMPDIR)/my_crate_name.exe &> $(TMPDIR)/backtrace.txt || exit 0
+	$(CGREP) "my_crate_name::main" < $(TMPDIR)/backtrace.txt
+	$(CGREP) "pdb-alt-path\\main.rs:2" < $(TMPDIR)/backtrace.txt
+
+	# Test that explicitly passed `-Clink-arg=/PDBALTPATH:...` is respected
+	$(RUSTC) main.rs -g --crate-name my_crate_name --crate-type bin -Clink-arg=/PDBALTPATH:abcdefg.pdb
+	$(CGREP) "abcdefg.pdb" < $(TMPDIR)/my_crate_name.exe
+	$(CGREP) -v "my_crate_name.pdb" < $(TMPDIR)/my_crate_name.exe

tests/run-make/pdb-alt-path/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    panic!("backtrace please");
+}