Merge #44

44: dedup contents of .cargo/config; don't depend on auto-load-safe-path being set r=ithinuel a=japaric

see individual commit messages for details

unfortunately this didn't come up as nice as I expected because there seems to
be a bug around `target.cfg.runner` (rust-lang/cargo#5946). Still, I think this
is an improvement.

r? @rust-embedded/cortex-m

Co-authored-by: Jorge Aparicio <jorge@japaric.io>

.cargo/config

@@ -1,5 +1,5 @@
-[target.thumbv6m-none-eabi]
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
-runner = 'arm-none-eabi-gdb'
+# runner = 'arm-none-eabi-gdb -x debug.gdb'
 rustflags = [
   # LLD (shipped with the Rust toolchain) is used as the default linker
   "-C", "link-arg=-Tlink.x",
@@ -16,41 +16,23 @@ rustflags = [
   # "-C", "link-arg=-nostartfiles",
 ]
 
+# work around rust-lang/cargo#5946
+[target.thumbv6m-none-eabi]
+runner = 'arm-none-eabi-gdb -x debug.gdb'
+
 [target.thumbv7m-none-eabi]
-runner = 'arm-none-eabi-gdb'
+runner = 'arm-none-eabi-gdb -x debug.gdb'
-rustflags = [
-  # the comments under `[target.thumbv6m-none-eabi]` also apply here
-  "-C", "link-arg=-Tlink.x",
-
-  # "-C", "linker=arm-none-eabi-ld",
-
-  # "-C", "linker=arm-none-eabi-gcc",
-  # "-C", "link-arg=-Wl,-Tlink.x",
-  # "-C", "link-arg=-nostartfiles",
-]
 
 [target.thumbv7em-none-eabi]
-runner = 'arm-none-eabi-gdb'
+runner = 'arm-none-eabi-gdb -x debug.gdb'
-rustflags = [
-  # the comments under `[target.thumbv6m-none-eabi]` also apply here
-  "-C", "link-arg=-Tlink.x",
-
-  # "-C", "linker=arm-none-eabi-ld",
-
-  # "-C", "linker=arm-none-eabi-gcc",
-  # "-C", "link-arg=-Wl,-Tlink.x",
-  # "-C", "link-arg=-nostartfiles",
-]
 
 [target.thumbv7em-none-eabihf]
-runner = 'arm-none-eabi-gdb'
+runner = 'arm-none-eabi-gdb -x debug.gdb'
-rustflags = [
+# end of workaround
-  # the comments under `[target.thumbv6m-none-eabi]` also apply here
-  "-C", "link-arg=-Tlink.x",
 
-  # "-C", "linker=arm-none-eabi-ld",
+[build]
-
+# Pick one of these compilation targets
-  # "-C", "linker=arm-none-eabi-gcc",
+# target = "thumbv6m-none-eabi"    # Cortex-M0 and Cortex-M0+
-  # "-C", "link-arg=-Wl,-Tlink.x",
+# target = "thumbv7m-none-eabi"    # Cortex-M3
-  # "-C", "link-arg=-nostartfiles",
+# target = "thumbv7em-none-eabi"   # Cortex-M4 and Cortex-M7 (no FPU)
-]
+# target = "thumbv7em-none-eabihf" # Cortex-M4F and Cortex-M7F (with FPU)