diff --git a/src/hx/libs/mysql/Build.xml b/src/hx/libs/mysql/Build.xml
index 76e497850..722c234c5 100644
--- a/src/hx/libs/mysql/Build.xml
+++ b/src/hx/libs/mysql/Build.xml
@@ -1,6 +1,7 @@
 <xml>
 
 <files id="hxcpp_mysql" dir="${this_dir}" >
+  <options name="Options.txt" ifExists="Options.txt"/>
   <depend files="hxcpp-depends"/>
   <depend name="${this_dir}/Build.xml" dateOnly="true" />
   <depend name="${this_dir}/sha1.h" />
diff --git a/src/hx/libs/regexp/Build.xml b/src/hx/libs/regexp/Build.xml
index 46a1fba14..fdfedeaae 100644
--- a/src/hx/libs/regexp/Build.xml
+++ b/src/hx/libs/regexp/Build.xml
@@ -27,6 +27,7 @@
 </files>
 
 <files id="hxcpp_regexp">
+  <options name="Options.txt" ifExists="Options.txt"/>
   <depend files="hxcpp-depends"/>
   <depend name="${this_dir}/Build.xml" dateOnly="true" />
   <cache value="true" asLibrary="true" />
diff --git a/src/hx/libs/sqlite/Build.xml b/src/hx/libs/sqlite/Build.xml
index b17ca5420..3b1596591 100644
--- a/src/hx/libs/sqlite/Build.xml
+++ b/src/hx/libs/sqlite/Build.xml
@@ -5,6 +5,7 @@
 <set name="SQLITE_DIR" value="${HXCPP}/project/thirdparty/sqlite-3.51.2"/>
 
 <files id="hxcpp_sqlite" dir="${this_dir}" >
+  <options name="Options.txt" ifExists="Options.txt"/>
   <depend files="hxcpp-depends"/>
   <depend name="${this_dir}/Build.xml" dateOnly="true" />
   <cache value="true" asLibrary="true" />
diff --git a/src/hx/libs/ssl/Build.xml b/src/hx/libs/ssl/Build.xml
index 2240f564a..98ad8d3e8 100644
--- a/src/hx/libs/ssl/Build.xml
+++ b/src/hx/libs/ssl/Build.xml
@@ -5,6 +5,7 @@
 <include name="${HXCPP}/project/thirdparty/mbedtls-files.xml" />
 
 <files id="hxcpp_ssl" >
+  <options name="Options.txt" ifExists="Options.txt"/>
 	<depend files="hxcpp-depends"/>
 	<depend name="${this_dir}/Build.xml" dateOnly="true" />
 	<cache value="true" asLibrary="true" />
diff --git a/src/hx/libs/std/Build.xml b/src/hx/libs/std/Build.xml
index f18ee01bb..3a790aea9 100644
--- a/src/hx/libs/std/Build.xml
+++ b/src/hx/libs/std/Build.xml
@@ -3,6 +3,7 @@
 <pragma once="true" />
 
 <files id="hxcpp_std" dir="${this_dir}" >
+  <options name="Options.txt" ifExists="Options.txt"/>
   <depend files="hxcpp-depends"/>
   <depend name="${this_dir}/Build.xml" dateOnly="true" />
   <cache value="1" asLibrary="true" />
diff --git a/src/hx/zip/Build.xml b/src/hx/zip/Build.xml
index 0cf31265b..cb9012da8 100644
--- a/src/hx/zip/Build.xml
+++ b/src/hx/zip/Build.xml
@@ -8,6 +8,7 @@
   <import name="${HXCPP_ZIP_XML}"/>
 
   <files id="hxcpp_zip_api">
+    <options name="Options.txt" ifExists="Options.txt"/>
     <cache value="true" asLibrary="true" />
 
     <depend files="hxcpp-depends"/>
diff --git a/src/hx/zip/zlib/Build.xml b/src/hx/zip/zlib/Build.xml
index 6289ab59f..6439b9590 100644
--- a/src/hx/zip/zlib/Build.xml
+++ b/src/hx/zip/zlib/Build.xml
@@ -31,6 +31,7 @@
   </files>
 
   <files id="hxcpp_zlib_impl" >
+    <options name="Options.txt" ifExists="Options.txt"/>
     <depend files="hxcpp-depends"/>
     <depend name="${this_dir}/Build.xml" dateOnly="true" />
     <depend name="${this_dir}/ZLibCompress.hpp"/>
diff --git a/tools/hxcpp/BuildTool.hx b/tools/hxcpp/BuildTool.hx
index cd5a48f5b..fcea8c4ab 100644
--- a/tools/hxcpp/BuildTool.hx
+++ b/tools/hxcpp/BuildTool.hx
@@ -1123,7 +1123,13 @@ class BuildTool
                case "hlsl" :
                   group.addHLSL( substitute(el.att.name), substitute(el.att.profile),
                   substitute(el.att.variable), substitute(el.att.target)  );
-               case "options" : group.addOptions( substitute(el.att.name) );
+               case "options" :
+                  // Resolved now, where ifExists is checked: an imported group is built from its own
+                  // directory, where a relative Options.txt would not be found.
+                  var options = substitute(el.att.name);
+                  if (!PathManager.isAbsolute(options))
+                     options = PathManager.combine(Sys.getCwd(), options);
+                  group.addOptions(options);
                case "config" : group.mConfig = substitute(el.att.name);
                case "assembler" : group.mAssembler = substitute(el.att.name);
                case "compilerflag" :
diff --git a/tools/hxcpp/FileGroup.hx b/tools/hxcpp/FileGroup.hx
index 355e41588..2d7ee7bba 100644
--- a/tools/hxcpp/FileGroup.hx
+++ b/tools/hxcpp/FileGroup.hx
@@ -204,7 +204,8 @@ class FileGroup
       var result = new Array<String>();
       for(def in contents.split("\n"))
       {
-         var name = def.split("=")[0];//.toLowerCase();
+         // Haxe writes defines as they were given, so -D HXCPP_M64 arrives upper case
+         var name = def.split("=")[0].toLowerCase();
          if (name.indexOf("hxcpp_link")>=0)
          {
             // Only effects linking, not compiling