diff --git a/patches/pkgbuild/gcc.sh b/patches/pkgbuild/gcc.sh
index 08ef9d2..f609691 100755
--- a/patches/pkgbuild/gcc.sh
+++ b/patches/pkgbuild/gcc.sh
@@ -91,6 +91,21 @@ sed -i '/usr\/lib32/d; /_libdir\/32/d' PKGBUILD
 # front end is off.
 sed -i 's/^\(\s*for _so in \).*; do$/\1libatomic.so libstdc++.so; do/' PKGBUILD
 
+# package_gcc() also _picks files out for every sub-package, including the
+# front ends we disabled. _pick is a mv, so it fails on what was never built:
+#
+#   mv: cannot stat 'usr/bin/gnat': No such file or directory
+#
+# Dropping the entries from pkgname was not enough -- the _pick lines live in
+# package_gcc() and run regardless of which sub-packages are requested.
+for _lang in gcc-ada gcc-d gcc-go gcc-m2 gcc-rust gcc-gcobol \
+             libgm2 libgo libgphobos libgcobol libhwasan; do
+    sed -i "/_pick ${_lang} /d" PKGBUILD
+done
+if grep -qE '_pick (gcc-ada|gcc-d|gcc-go|gcc-m2|gcc-rust|gcc-gcobol) ' PKGBUILD; then
+    echo "gcc: _pick lines remain for a disabled front end" >&2; exit 1
+fi
+
 if grep -q 'usr/lib32' PKGBUILD; then
     echo "gcc: usr/lib32 still manipulated" >&2; exit 1
 fi
diff --git a/scripts/bootstrap-pacman.sh b/scripts/bootstrap-pacman.sh
index 31325ba..fb489b8 100755
--- a/scripts/bootstrap-pacman.sh
+++ b/scripts/bootstrap-pacman.sh
@@ -123,8 +123,15 @@ build_package() {
     # success became the function's exit status -- and a run reported
     # "51 built, 0 failed" while glibc, gcc, coreutils and pacman had all
     # failed. Measured: the repository held 23 files, not a hundred.
-    makepkg --nodeps --ignorearch --skippgpcheck --skipchecksums --nocheck -f \
-        || return 1
+    # -C wipes $srcdir first. Without it a re-run inherits the previous
+    # attempt's tree, and prepare() fails on work it already did:
+    #   patch: ... already exists!  Skipping patch.
+    #   1 out of 1 hunk ignored
+    #   mkdir: build-curl-compat: File exists
+    # grep, gnupg, pacman and curl all failed this way -- not on the
+    # port, but on my own driver re-entering a dirty directory.
+    makepkg --nodeps --ignorearch --skippgpcheck --skipchecksums --nocheck \
+        -C -f || return 1
     # An exit code is not proof. Only the artefact is.
     local produced=()
     shopt -s nullglob