OSCSender.cpp does not compile

[gigo@…]

% ./configure --prefix=/usr/local/drobilla-lad
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Configuration:

Jack support: yes
Jack D-Bus support: no
LV2 Plugin support: yes
LADSPA Plugin support: yes
D-BUS support: yes

LADSPA plugin install location: ${exec_prefix}/lib/ladspa
LV2 plugin install location: ${exec_prefix}/lib/lv2

FlowCanvas?:

Anti-Aliasing: yes

Ingen:

Denormal fixes (assembly): yes
Engine library/OSC server: yes
JACK in-process engine: no
Client library: yes
GTK GUI: yes
OSC interface (via liblo): yes
HTTP interface (libsoup): no
Language bindings: no

Build unit tests: no

* CHECK THE ABOVE AND SEE YOU'RE ACTUALLY BUILDING WHAT YOU WANT *

C FLAGS: -g -O2 -DNDEBUG -std=c99 -pipe -fmessage-length=999 -DCONFIG_H_PATH=\"/usr/src/handmade/drobilla-lad/config/config.h\"
C++ FLAGS: -g -O2 -DNDEBUG -ansi -pipe -fmessage-length=999 -DCONFIG_H_PATH=\"/usr/src/handmade/drobilla-lad/config/config.h\"
Please note the above and see README for performance information.

% make
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g++ -DHAVE_CONFIG_H -I. -I../../../../config -I/usr/include/glibmm-2.4 -I/usr/lib/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib/sigc++-2.0/include -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/src/handmade/drobilla-lad/ingen/src/common -I/usr/src/handmade/drobilla-lad/ingen/src/libs -I/usr/src/handmade/drobilla-lad/ingen/src/libs/engine/events -I/usr/src/handmade/drobilla-lad/ingen/src -I/usr/src/handmade/drobilla-lad/raul -I/usr/include/rasqal -I/usr/src/handmade/drobilla-lad/redlandmm -I/usr/src/handmade/drobilla-lad/lv2core -I/usr/src/handmade/drobilla-lad/slv2 -g -O2 -DNDEBUG -ansi -pipe -fmessage-length=999 -DCONFIG_H_PATH=\"/usr/src/handmade/drobilla-lad/config/config.h\" -MT libingen_shared_la-OSCSender.lo -MD -MP -MF .deps/libingen_shared_la-OSCSender.Tpo -c OSCSender.cpp -o libingen_shared_la-OSCSender.o

OSCSender.cpp: In member function 'int Ingen::Shared::OSCSender::send(const char*, const char*, ...)':
OSCSender.cpp:84: error: 'va_start' was not declared in this scope
OSCSender.cpp:87: error: 'lo_message_add_varargs' was not declared in this scope
OSCSender.cpp:92: error: 'va_end' was not declared in this scope
make[4]: * [libingen_shared_la-OSCSender.lo] Error 1
make[4]: Leaving directory `/usr/src/handmade/drobilla-lad/ingen/src/libs/shared'
make[3]: * [all-recursive] Error 1
make[3]: Leaving directory `/usr/src/handmade/drobilla-lad/ingen/src/libs'
make[2]: * [all-recursive] Error 1
make[2]: Leaving directory `/usr/src/handmade/drobilla-lad/ingen/src'
make[1]: * [all-recursive] Error 1
make[1]: Leaving directory `/usr/src/handmade/drobilla-lad/ingen'
make: * [all-recursive] Error 1
% gcc --version
gcc (Debian 4.3.2-1) 4.3.2
(...)
% ld --version
GNU ld (GNU Binutils for Debian) 2.18.0.20080103
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