inkscape.sty

% automagically re-export the svgs to pdf_tex format
% requires inkscape. modify the path below as appropriate
% requires the '-shell-escape' flag to be passed to the latex compiler

\ProvidesPackage{inkscape}

%% change the variable below to suit your installation
\def\inkscape{/Applications/Inkscape.app/Contents/Resources/bin/inkscape }

%% command that checks for changes to the .svg file and
%% automatically re-exports it, as needed
\newcommand{\executeiffilenewer}[3]{%
  \ifnum\pdfstrcmp{\pdffilemoddate{#1}}%
  {\pdffilemoddate{#2}}>0%
  {\immediate\write18{#3}}\fi%
} 

%% wrapper for \executeiffilenewer and importer for the resulting format
\newcommand{\includesvg}[1]{%
  \executeiffilenewer{#1.svg}{#1.pdf}%
  {\inkscape -z -D --file=#1.svg --export-pdf=#1.pdf --export-latex}%
  \input{#1.pdf_tex}%
}