treewide: rename bad filenames

Most of these can easily be moved to subdirectories of other
directories. This helps reduce clutter in the main trees.

pkgs/development/misc/stm32/betaflight/default.nix

@@ -0,0 +1,65 @@
+{ stdenv, fetchFromGitHub
+, gcc-arm-embedded, python2
+, skipTargets ? [
+  # These targets do not build for various unexplored reasons
+  # TODO ... fix them
+  "AFROMINI"
+  "ALIENWHOOP"
+  "BEEBRAIN"
+  "CJMCU"
+  "FRSKYF3"
+]}:
+
+let
+
+  version = "3.2.3";
+
+in stdenv.mkDerivation rec {
+
+  name = "betaflight-${version}";
+
+  src = fetchFromGitHub {
+    owner = "betaflight";
+    repo = "betaflight";
+    rev = "v${version}";
+    sha256 = "0vbjyxfjxgpaiiwvj5bscrlfikzp3wnxpmc4sxcz5yw5mwb9g428";
+  };
+
+  buildInputs = [
+    gcc-arm-embedded
+    python2
+  ];
+
+  postPatch = ''
+    sed -ri "s/REVISION.*=.*git log.*/REVISION = ${builtins.substring 0 9 src.rev}/" Makefile # Let's not require git in shell
+    sed -ri "s/binary hex/hex/" Makefile # No need for anything besides .hex
+  '';
+
+  enableParallelBuilding = true;
+
+  preBuild = ''
+    buildFlagsArray=(
+      "SKIP_TARGETS=${toString skipTargets}"
+      "GCC_REQUIRED_VERSION=$(arm-none-eabi-gcc -dumpversion)"
+      all
+    )
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mkdir -p $out
+    cp obj/*.hex $out
+
+    runHook postInstall
+  '';
+
+  meta = with stdenv.lib; {
+    description = "Flight controller software (firmware) used to fly multi-rotor craft and fixed wing craft";
+    homepage = https://github.com/betaflight/betaflight;
+    license = licenses.gpl3;
+    maintainers = with maintainers; [ elitak ];
+    platforms = platforms.linux;
+  };
+
+}