diff --git a/third_party/build/gsm/config.h b/third_party/build/gsm/config.h
new file mode 100644
index 0000000..a7fec50
--- /dev/null
+++ b/third_party/build/gsm/config.h
@@ -0,0 +1,11 @@
+#ifdef _MSC_VER
+#   pragma warning(disable: 4100)   // unreferenced formal parameter
+#   pragma warning(disable: 4101)   // unreferenced local variable
+#   pragma warning(disable: 4244)   // conversion from 'double ' to 'float '
+#   pragma warning(disable: 4305)   // truncation from 'const double ' to 'float '
+#   pragma warning(disable: 4018)   // signed/unsigned mismatch
+//#   pragma warning(disable: 4701)   // local variable used without initialized
+#endif
+
+#include <string.h>
+#include "../../gsm/inc/config.h"
diff --git a/third_party/build/gsm/libgsmcodec.dsp b/third_party/build/gsm/libgsmcodec.dsp
new file mode 100644
index 0000000..872cbf0
--- /dev/null
+++ b/third_party/build/gsm/libgsmcodec.dsp
@@ -0,0 +1,194 @@
+# Microsoft Developer Studio Project File - Name="libgsmcodec" - Package Owner=<4>
+# Microsoft Developer Studio Generated Build File, Format Version 6.00
+# ** DO NOT EDIT **
+
+# TARGTYPE "Win32 (x86) Static Library" 0x0104
+
+CFG=libgsmcodec - Win32 Debug
+!MESSAGE This is not a valid makefile. To build this project using NMAKE,
+!MESSAGE use the Export Makefile command and run
+!MESSAGE 
+!MESSAGE NMAKE /f "libgsmcodec.mak".
+!MESSAGE 
+!MESSAGE You can specify a configuration when running NMAKE
+!MESSAGE by defining the macro CFG on the command line. For example:
+!MESSAGE 
+!MESSAGE NMAKE /f "libgsmcodec.mak" CFG="libgsmcodec - Win32 Debug"
+!MESSAGE 
+!MESSAGE Possible choices for configuration are:
+!MESSAGE 
+!MESSAGE "libgsmcodec - Win32 Release" (based on "Win32 (x86) Static Library")
+!MESSAGE "libgsmcodec - Win32 Debug" (based on "Win32 (x86) Static Library")
+!MESSAGE 
+
+# Begin Project
+# PROP AllowPerConfigDependencies 0
+# PROP Scc_ProjName ""
+# PROP Scc_LocalPath ""
+CPP=cl.exe
+RSC=rc.exe
+
+!IF  "$(CFG)" == "libgsmcodec - Win32 Release"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 0
+# PROP BASE Output_Dir "output\gsm-i386-vc6-release"
+# PROP BASE Intermediate_Dir "output\gsm-i386-vc6-release"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 0
+# PROP Output_Dir "output\gsm-i386-vc6-release"
+# PROP Intermediate_Dir "output\gsm-i386-vc6-release"
+# PROP Target_Dir ""
+F90=df.exe
+# ADD BASE CPP /nologo /W3 /GX /O2 /D "WIN32" /D "NDEBUG" /D "_MBCS" /D "_LIB" /YX /FD /c
+# ADD CPP /nologo /W1 /GX /O2 /I "." /I "../../gsm/inc" /D "WIN32" /D "NDEBUG" /D "_MBCS" /D "_LIB" /YX /FD /c
+# ADD BASE RSC /l 0x409 /d "NDEBUG"
+# ADD RSC /l 0x409 /d "NDEBUG"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LIB32=link.exe -lib
+# ADD BASE LIB32 /nologo
+# ADD LIB32 /nologo /out:"..\..\lib\libgsmcodec-i386-vc6-release.lib"
+
+!ELSEIF  "$(CFG)" == "libgsmcodec - Win32 Debug"
+
+# PROP BASE Use_MFC 0
+# PROP BASE Use_Debug_Libraries 1
+# PROP BASE Output_Dir "output\gsm-i386-vc6-debug"
+# PROP BASE Intermediate_Dir "output\gsm-i386-vc6-debug"
+# PROP BASE Target_Dir ""
+# PROP Use_MFC 0
+# PROP Use_Debug_Libraries 1
+# PROP Output_Dir "output\gsm-i386-vc6-debug"
+# PROP Intermediate_Dir "output\gsm-i386-vc6-debug"
+# PROP Target_Dir ""
+F90=df.exe
+# ADD BASE CPP /nologo /W3 /Gm /GX /ZI /Od /D "WIN32" /D "_DEBUG" /D "_MBCS" /D "_LIB" /YX /FD /GZ /c
+# ADD CPP /nologo /W2 /Gm /GX /ZI /Od /I "." /I "../../gsm/inc" /D "WIN32" /D "_DEBUG" /D "_MBCS" /D "_LIB" /YX /FD /GZ /c
+# ADD BASE RSC /l 0x409 /d "_DEBUG"
+# ADD RSC /l 0x409 /d "_DEBUG"
+BSC32=bscmake.exe
+# ADD BASE BSC32 /nologo
+# ADD BSC32 /nologo
+LIB32=link.exe -lib
+# ADD BASE LIB32 /nologo
+# ADD LIB32 /nologo /out:"..\..\lib\libgsmcodec-i386-vc6-debug.lib"
+
+!ENDIF 
+
+# Begin Target
+
+# Name "libgsmcodec - Win32 Release"
+# Name "libgsmcodec - Win32 Debug"
+# Begin Group "Source Files"
+
+# PROP Default_Filter "cpp;c;cxx;rc;def;r;odl;idl;hpj;bat"
+# Begin Source File
+
+SOURCE=..\..\gsm\src\add.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\code.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\debug.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\decode.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_create.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_decode.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_destroy.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_encode.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_explode.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_implode.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_option.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\gsm_print.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\long_term.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\lpc.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\preprocess.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\rpe.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\short_term.c
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\src\table.c
+# End Source File
+# End Group
+# Begin Group "Header Files"
+
+# PROP Default_Filter "h;hpp;hxx;hm;inl"
+# Begin Source File
+
+SOURCE=.\config.h
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\inc\config.h
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\inc\gsm.h
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\inc\private.h
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\inc\proto.h
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\inc\toast.h
+# End Source File
+# Begin Source File
+
+SOURCE=..\..\gsm\inc\unproto.h
+# End Source File
+# End Group
+# End Target
+# End Project