Get `gn gen` to succeed on Windows

third_party/sqlite/src/README

+This directory contains source code to 
+
+    SQLite: An Embeddable SQL Database Engine
+
+To compile the project, first create a directory in which to place
+the build products.  It is recommended, but not required, that the
+build directory be separate from the source directory.  Cd into the
+build directory and then from the build directory run the configure
+script found at the root of the source tree.  Then run "make".
+
+For example:
+
+    tar xzf sqlite.tar.gz    ;#  Unpack the source tree into "sqlite"
+    mkdir bld                ;#  Build will occur in a sibling directory
+    cd bld                   ;#  Change to the build directory
+    ../sqlite/configure      ;#  Run the configure script
+    make                     ;#  Run the makefile.
+    make install             ;#  (Optional) Install the build products
+
+The configure script uses autoconf 2.61 and libtool.  If the configure
+script does not work out for you, there is a generic makefile named
+"Makefile.linux-gcc" in the top directory of the source tree that you
+can copy and edit to suit your needs.  Comments on the generic makefile
+show what changes are needed.
+
+The linux binaries on the website are created using the generic makefile,
+not the configure script.  The windows binaries on the website are created
+using MinGW32 configured as a cross-compiler running under Linux.  For 
+details, see the ./publish.sh script at the top-level of the source tree.
+The developers do not use teh configure script.
+
+SQLite does not require TCL to run, but a TCL installation is required
+by the makefiles.  SQLite contains a lot of generated code and TCL is
+used to do much of that code generation.  The makefile also requires
+AWK.
+
+Contacts:
+
+   http://www.sqlite.org/