Fix inplace build

build_dso for inplace mode copies DSO built in build/ into worktree.
However if the destination directory does not exist yet, copy_file
fails. Fix it by making sure before copying that destination directory
exits.

Without the fix added test fails as follows:

    ...
    creating build/lib.linux-x86_64-2.7
    creating build/lib.linux-x86_64-2.7/dsodemo
    creating build/lib.linux-x86_64-2.7/dsodemo/lib
    x86_64-linux-gnu-g++ -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-z,relro -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-IbFBHb/python2.7-2.7.16=. -fstack-protector-strong -Wformat -Werror=format-security -Wl,-z,relro -Wdate-time -D_FORTIFY_SOURCE=2 -g -fdebug-prefix-map=/build/python2.7-IbFBHb/python2.7-2.7.16=. -fstack-protector-strong -Wformat -Werror=format-security build/temp.linux-x86_64-2.7/foo.o build/temp.linux-x86_64-2.7/bar.o -o build/lib.linux-x86_64-2.7/dsodemo/lib/libdemo.so.1.0 -Wl,-h,libdemo.so.1.0
    symlink libdemo.so.1.0 -> build/lib.linux-x86_64-2.7/dsodemo/lib/libdemo.so.1.0
    copying build/lib.linux-x86_64-2.7/dsodemo/lib/libdemo.so.1.0 -> dsodemo/lib
    error: [Errno 2] No such file or directory: 'dsodemo/lib/libdemo.so.1.0'

src/setuptools_dso/dsocmd.py

@@ -330,6 +330,7 @@ class build_dso(dso2libmixin, Command):
             #self.copy_file(outlib, outbaselib) # link="sym" seem to get the target path wrong
 
         if self.inplace:
+            self.mkpath(os.path.dirname(solib))
             self.copy_file(outlib, solib)
             if baselib!=solib:
                 self.copy_file(outbaselib, baselib)

testme.sh

 #!/bin/sh
 set -e
 
+die() {
+    echo "$@" 1>&2
+    exit 1
+}
+
 [ -d src/setuptools_dso ] || exit 2
 
 PYTHON="$1"
@@ -15,9 +20,22 @@ virtualenv env
 "$PYTHON" setup.py clean -a
 "$PYTHON" setup.py -v install
 
+# inplace build
+echo -e '\n* inplace build\n'
 cd example
+"$PYTHON" setup.py clean -a
+git clean -fdx	# `setup.py clean` does not clean inplace built files
+"$PYTHON" -m dsodemo.cli 2>/dev/null && die "error: worktree must be clean"
+"$PYTHON" setup.py -v build_dso -i
+"$PYTHON" setup.py -v build_ext -i
+"$PYTHON" -m dsodemo.cli
+
 
+# build + install
+echo -e '\n* build + install\n'
 "$PYTHON" setup.py clean -a
+git clean -fdx
+"$PYTHON" -m dsodemo.cli 2>/dev/null && die "error: worktree must be clean"
 "$PYTHON" setup.py -v install
 
 cd ..