Fixes for Windows mswin & sqlcipher

.github/workflows/sqlite3-ruby.yml

@@ -84,11 +84,8 @@ jobs:
         include:
           - os: "windows-2022"
             ruby: "mingw"
-          # # I'm struggling to build against sqlcipher on mswin.
-          # # find_header can't find sqlite3.h
-          # # patches welcome from anyone who needs this functionality and can make it work.
-          # - os: "windows-2022"
-          #   ruby: "mswin"
+          - os: "windows-2022"
+            ruby: "mswin"
     runs-on: ${{matrix.os}}
     steps:
       - if: matrix.os == 'windows-2022'
@@ -104,6 +101,6 @@ jobs:
           apt-get: "libsqlcipher-dev"
           brew: "sqlcipher"
           mingw: "sqlcipher"
-          # vcpkg: "sqlcipher" # see above
+          vcpkg: "sqlcipher"
       - run: bundle exec rake compile -- --with-sqlcipher
       - run: bundle exec rake test

ext/sqlite3/extconf.rb

@@ -44,7 +44,7 @@ def sqlcipher?
 
       def configure_system_libraries
         pkg_config(libname)
-        append_cflags("-DUSING_SQLCIPHER") if sqlcipher?
+        append_cppflags("-DUSING_SQLCIPHER") if sqlcipher?
       end
 
       def configure_packaged_libraries
@@ -75,10 +75,17 @@ def configure_packaged_libraries
 
       def configure_extension
         if Gem::Requirement.new("< 2.7").satisfied_by?(Gem::Version.new(RUBY_VERSION))
-          append_cflags("-DTAINTING_SUPPORT")
+          append_cppflags("-DTAINTING_SUPPORT")
+        end
+
+        if find_header("sqlite3.h")
+          # noop
+        elsif sqlcipher? && find_header("sqlcipher/sqlite3.h")
+          append_cppflags("-DUSING_SQLCIPHER_INC_SUBDIR")
+        else
+          abort_could_not_find("sqlite3.h")
         end
 
-        abort_could_not_find("sqlite3.h") unless find_header("sqlite3.h")
         abort_could_not_find(libname) unless find_library(libname, "sqlite3_libversion_number", "sqlite3.h")
 
         # Functions defined in 1.9 but not 1.8

ext/sqlite3/sqlite3_ruby.h

@@ -21,8 +21,11 @@
 #define SQLITE3_UTF8_STR_NEW2(_obj) \
     (rb_enc_associate_index(rb_str_new2(_obj), rb_utf8_encindex()))
 
-
-#include <sqlite3.h>
+#ifdef USING_SQLCIPHER_INC_SUBDIR
+#  include <sqlcipher/sqlite3.h>
+#else
+#  include <sqlite3.h>
+#endif
 
 #ifndef HAVE_TYPE_SQLITE3_INT64
 typedef sqlite_int64 sqlite3_int64;