[wpimath] Explicitly export wpimath symbols

Co-authored-by: Tyler Veness <calcmogul@gmail.com>

shared/jni/setupBuild.gradle

@@ -59,6 +59,8 @@ model {
                     it.buildable = false
                     return
                 }
+                it.cppCompiler.define 'WPILIB_EXPORTS'
+                it.cCompiler.define 'WPILIB_EXPORTS'
                 if (!project.hasProperty('noWpiutil')) {
                     lib project: ':wpiutil', library: 'wpiutil', linkage: 'shared'
                 }