sqlcipher: iOS cross-compilation support

- postPatch: sqlcipher uses autosetup, which ships config.sub/config.guess
  under autosetup/ with an 'autosetup-' prefix — outside the default
  updateAutotoolsGnuConfigScriptsHook file-name glob. Refresh them from
  gnu-config so new triples (e.g. aarch64-apple-ios-simulator) are
  recognized. Also patch src/shell.c.in to stub system() calls on iOS
  (API forbidden).
- configureFlags: --disable-readline on iOS (ncurses has no shared libs);
  --disable-tcl for any cross build (TCL nativeBuildInput is build-platform
  and can't be linked into a different-arch target).
- buildInputs: drop readline/ncurses on iOS (ncurses has no shared libs there).
- postInstall: iOS produces .so (not .dylib). Gate the Darwin dylib-symlink
  block on !isiOS and add an iOS .so-symlink block. Remove stale libsqlite3*
  symlinks before renaming.
- TCLLIBDIR: only set when not cross-compiling.

Author: insipx

pkgs/by-name/sq/sqlcipher/package.nix

@@ -28,22 +28,51 @@ stdenv.mkDerivation (finalAttrs: {
     util-linux
   ];
 
+  # readline/ncurses back the interactive CLI; iOS has no shared ncurses.
   buildInputs = [
-    readline
-    ncurses
     openssl
     zlib
+  ]
+  ++ lib.optionals (!stdenv.hostPlatform.isiOS) [
+    readline
+    ncurses
   ];
 
   depsBuildBuild = [
     buildPackages.stdenv.cc
   ];
 
+  # Refresh sqlcipher's autosetup-bundled config.sub/config.guess from gnu-config —
+  # they live under autosetup/ with an autosetup- prefix, outside the default
+  # updateAutotoolsGnuConfigScriptsHook glob, so new triples (e.g.
+  # aarch64-apple-ios-simulator) wouldn't be recognized otherwise.
+  postPatch = ''
+    for script in config.sub config.guess; do
+      if [ -f "autosetup/autosetup-$script" ]; then
+        cp -f "${buildPackages.gnu-config}/$script" "autosetup/autosetup-$script"
+      fi
+    done
+  ''
+  + lib.optionalString stdenv.hostPlatform.isiOS ''
+    # iOS forbids system(); stub the three CLI shell call sites.
+    sed -i -e 's|rc = system(zCmd);|rc = -1;|g' \
+           -e 's|if( system(zCmd) ){|if( -1 ){|g' \
+           -e 's|x = zCmd!=0 ? system(zCmd) : 1;|x = zCmd!=0 ? -1 : 1;|g' \
+           src/shell.c.in
+  '';
+
   configureFlags = [
     "--enable-threadsafe"
-    "--with-readline-inc=-I${lib.getDev readline}/include"
     "--enable-load-extension"
-  ];
+    (
+      if stdenv.hostPlatform.isiOS then
+        "--disable-readline"
+      else
+        "--with-readline-inc=-I${lib.getDev readline}/include"
+    )
+  ]
+  # TCL is a nativeBuildInput (build-platform arch), can't link into a cross target.
+  ++ lib.optionals (stdenv.buildPlatform != stdenv.hostPlatform) [ "--disable-tcl" ];
 
   env = {
     NIX_CFLAGS_COMPILE = toString [
@@ -59,6 +88,8 @@ stdenv.mkDerivation (finalAttrs: {
       "-lcrypto"
     ];
     BUILD_CC = "$(CC_FOR_BUILD)";
+  }
+  // lib.optionalAttrs (stdenv.buildPlatform == stdenv.hostPlatform) {
     TCLLIBDIR = "${placeholder "out"}/lib/tcl${lib.versions.majorMinor tcl.version}";
   };
 
@@ -69,7 +100,9 @@ stdenv.mkDerivation (finalAttrs: {
     mv $out/include/sqlite3.h $out/include/sqlcipher/sqlite3.h
     mv $out/include/sqlite3ext.h $out/include/sqlcipher/sqlite3ext.h
     mv $out/lib/lib{sqlite3,sqlcipher}.a
+    # Remove stale libsqlite3 symlinks before renaming — their targets will be gone after rename.
     rm -f $out/lib/libsqlite3.0.dylib $out/lib/libsqlite3.dylib $out/lib/libsqlite3.so $out/lib/libsqlite3.so.0
+    find $out/lib -maxdepth 1 -type l -name 'libsqlite3*' -delete
     rename libsqlite3 libsqlcipher $out/lib/libsqlite3*
     mv $out/lib/pkgconfig/{sqlite3,sqlcipher}.pc
     mv $out/share/man/man1/{sqlite3,sqlcipher}.1
@@ -78,7 +111,7 @@ stdenv.mkDerivation (finalAttrs: {
       --replace-fail "-lz" "-lz -lcrypto" \
       --replace-fail "includedir}" "includedir}/sqlcipher"
   ''
-  + lib.optionalString stdenv.hostPlatform.isDarwin ''
+  + lib.optionalString (stdenv.hostPlatform.isDarwin && !stdenv.hostPlatform.isiOS) ''
     f=$(echo $out/lib/libsqlcipher.*.dylib)
     ln --symbolic --force "$f" $out/lib/libsqlcipher.0.dylib
     ln --symbolic --force "$f" $out/lib/libsqlcipher.dylib
@@ -88,6 +121,13 @@ stdenv.mkDerivation (finalAttrs: {
     f=$(echo $out/lib/libsqlcipher.so.*)
     ln --symbolic --force "$f" $out/lib/libsqlcipher.so.0
     ln --symbolic --force "$f" $out/lib/libsqlcipher.so
+  ''
+  + lib.optionalString stdenv.hostPlatform.isiOS ''
+    # iOS ships the versioned .so as libsqlcipher.<version>.so (no .so.<version>).
+    f=$(echo $out/lib/libsqlcipher.*.so)
+    ln -sf "$f" $out/lib/libsqlcipher.0.so
+    ln -sf "$f" $out/lib/libsqlcipher.so
+    ln -sf "$f" $out/lib/libsqlite3.so
   '';
 
   meta = {