debian: Skip everything but ports/posix/snek for -arch builds

This avoids re-building docs and running black

Signed-off-by: Keith Packard <keithp@keithp.com>

debian/control

@@ -4,13 +4,13 @@ Priority: optional
 Maintainer: Keith Packard <keithp@keithp.com>
 Homepage: https://keithp.com
 Rules-Requires-Root: no
-Build-Depends: debhelper-compat (= 13), libreadline-dev,
- python3, lola, gawk, asciidoctor, ruby-asciidoctor-pdf, ruby-coderay,
- black
+Build-Depends: debhelper-compat (= 13), libreadline-dev, python3, lola, gawk
 Build-Depends-Indep: avr-libc, gcc-avr,
  binutils-arm-none-eabi, gcc-arm-none-eabi, picolibc-arm-none-eabi (>= 1.4), qemu-system-arm,
  binutils-riscv64-unknown-elf, gcc-riscv64-unknown-elf, picolibc-riscv64-unknown-elf (>= 1.4),
- gcc-arm-linux-gnueabi, libc6-dev-armel-cross
+ gcc-arm-linux-gnueabi, libc6-dev-armel-cross,
+ asciidoctor, ruby-asciidoctor-pdf, ruby-coderay,
+ black
 Standards-Version: 4.5.0
 
 Package: snek

debian/rules

@@ -40,10 +40,10 @@ override_dh_auto_build-indep:
 	dh_auto_build -- "SNEK_MOST_WARNINGS=$(SNEK_MOST_WARNINGS)"
 
 override_dh_auto_build-arch:
-	dh_auto_build -- FIRMWARE= "SNEK_MOST_WARNINGS=$(SNEK_MOST_WARNINGS)"
+	dh_auto_build -- -C ports/posix SUBDIRS= FIRMWARE= "SNEK_MOST_WARNINGS=$(SNEK_MOST_WARNINGS)"
 
 override_dh_auto_test-arch:
-	dh_auto_test -- FIRMWARE= SNEK_RISCV= SNEK_ARM=
+	dh_auto_test -- -C test FIRMWARE= SNEK_RISCV= SNEK_ARM=
 
 override_dh_auto_install-arch:
-	dh_auto_install -- FIRMWARE=
+	dh_auto_install -- -C ports/posix