Add descriptive header to tool scripts.

tools/gen_cyglto_dll.sh

@@ -1,4 +1,8 @@
 #!/usr/bin/env bash
+#
+# Build and install the LTO library, which the Cygwin package of
+# libLLVM is lacking.
+#
 
 pushd "${0%/*}/.." &>/dev/null
 source tools/tools.sh

tools/gen_sdk_package.sh

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
-# OS X SDK packaging script
+#
+# Package the OS X SDKs into a tar file to be used by `build.sh`.
+#
 
 export LC_ALL=C
 

tools/gen_sdk_package_darling_dmg.sh

@@ -1,4 +1,13 @@
 #!/usr/bin/env bash
+#
+# Mount a Xcode .dmg (using fuse) and run gen_sdk_package.sh.
+#
+# Works up to Xcode 7.3
+#
+# This script uses darling-dmg and fuse to mount the .dmg, thus
+# avoiding to actually unpack it.
+# darling-dmg will be downloaded and compiled if missing.
+#
 
 pushd "${0%/*}/.." &>/dev/null
 source tools/tools.sh

tools/gen_sdk_package_p7zip.sh

@@ -1,4 +1,12 @@
 #!/usr/bin/env bash
+#
+# Extract required files from a Xcode .dmg using p7zip and run
+# gen_sdk_package.sh.
+#
+# Works up to Xcode 7.2
+#
+# p7zip will be downloaded and compiled if missing.
+#
 
 pushd "${0%/*}/.." &>/dev/null
 source tools/tools.sh

tools/mount_xcode_image.sh

@@ -1,4 +1,9 @@
 #!/usr/bin/env bash
+#
+# Mount a Xcode .dmg (requires root) and run gen_sdk_package.sh.
+#
+# Works up to Xcode 4.2
+#
 
 if [ $(uname -s) != "Linux" ]; then
   echo "This script must be run on Linux"