Microchip's XC8 Linker doesn't recognize some custom section names
I submitted a ticket to Microchip's tech support, and after a few days, they found that

 #pragma psect &lt;default_section&gt;=&lt;new_section&gt;


would work for constants just like it's supposed to.  They've made a note of the problem and said they'd fix it in the next release so either that or __section("new_section") will also work for constants.

I don't like the #pragma because you have to know the default_section (can be found by compiling successfully without the directive and searching the map file) and because it affects the entire source file, while __section() only affects the one item that it's used with.  But for my application, it works.