Bug#732187: missing dependency on libpng12-dev?

[Peter Eisentraut]

Package: libgtk2.0-dev
Version: 2.24.22-1
Severity: important

$ pkg-config --cflags gtk+-2.0
Package libpng12 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libpng12.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libpng12', required by 'GdkPixbuf', not found

If I install the libpng12-dev package, then it works as expected.

This is currently causing the pinentry package to fail to build,
possibly others as well.

-- System Information:
Debian Release: jessie/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable'), (500, 'stable'), (101, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.10-3-686-pae (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages libgtk2.0-dev depends on:
ii  gir1.2-gtk-2.0        2.24.22-1
ii  libatk1.0-dev         2.10.0-2
ii  libcairo2-dev         1.12.16-2
ii  libgdk-pixbuf2.0-dev  2.28.2-1+b1
ii  libglib2.0-dev        2.36.4-1
ii  libgtk2.0-0           2.24.22-1
ii  libgtk2.0-common      2.24.22-1
ii  libpango1.0-dev       1.36.0-1
ii  libx11-dev            2:1.6.2-1
ii  libxcomposite-dev     1:0.4.4-1
ii  libxcursor-dev        1:1.1.14-1
ii  libxdamage-dev        1:1.1.4-1
ii  libxext-dev           2:1.3.2-1
ii  libxfixes-dev         1:5.0.1-1
ii  libxi-dev             2:1.7.2-1
ii  libxinerama-dev       2:1.1.3-1
ii  libxml2-utils         2.9.1+dfsg1-3
ii  libxrandr-dev         2:1.4.1-1
ii  pkg-config            0.26-1

Versions of packages libgtk2.0-dev recommends:
ii  debhelper  9.20131127
ii  python     2.7.5-5

Versions of packages libgtk2.0-dev suggests:
pn  libgtk2.0-doc  <none>

-- no debconf information