New recipe: gflags v2.2.2 (#4751)

* Add gflags build_tarball.jl

* Fix dirname

* Update G/gflags/build_tarballs.jl

Co-authored-by: Mosè Giordano <[email protected]>

Co-authored-by: Mosè Giordano <[email protected]>

Author: doriantsolak

G/gflags/build_tarballs.jl

@@ -0,0 +1,43 @@
+# Note that this script can accept some limited command-line arguments, run
+# `julia build_tarballs.jl --help` to see a usage message.
+using BinaryBuilder, Pkg
+
+name = "gflags"
+version = v"2.2.2"
+
+# Collection of sources required to complete build
+sources = [
+    GitSource("https://github.com/gflags/gflags.git", "986e8eed00ded8168ef4eaa6f925dc6be50b40fa")
+]
+
+# Bash recipe for building across all platforms
+script = raw"""
+cd $WORKSPACE/srcdir/gflags/
+mkdir build
+cd build
+cmake -DCMAKE_INSTALL_PREFIX=${prefix} \
+    -DCMAKE_TOOLCHAIN_FILE=${CMAKE_TARGET_TOOLCHAIN} \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DBUILD_SHARED_LIBS=ON \
+    ..
+make -j${nproc}
+make install
+"""
+
+# These are the platforms we will build for by default, unless further
+# platforms are passed in on the command line
+platforms = supported_platforms()
+platforms = expand_cxxstring_abis(platforms)
+
+# The products that we will ensure are always built
+products = [
+    LibraryProduct("libgflags", :gflags),
+    LibraryProduct("libgflags_nothreads", :gflags_nt)
+]
+
+# Dependencies that must be installed before this package can be built
+dependencies = Dependency[
+]
+
+# Build the tarballs, and possibly a `build.jl` as well.
+build_tarballs(ARGS, name, version, sources, script, platforms, products, dependencies; julia_compat="1.6")