{
    local $/;  # go to slurp mode for input
    open( I, "<", "my_source_code" ) or die "my_source_code: $!";
    $_ = <I>;
    close I;

    s/(if.*?)\s+{/$1 {/g;    # fix spacing/line-breaks for "if .... {"

    open( O, ">", "my_new_source_code" ) or die "my_new_source_code: $!";
    print O;
    close O;
}

##</code><code>##

if ( "blah { blah } blah" )

{
...

##</code><code>##

     s/(if.*?\))[ \r\t]*\n\s+{/$1 {/;  # fix spacing/line-breaks for "if (...) {"