This is complicated by the fact extern on a function declaration implies
visibility... we have to make LWS_EXTERN empty when building static.
And, setting target_compile_definitions() doesn't work inside macros,
so it has to be set explicitly for the plugins.
Checking the symbol status needs nm -C -D as per
https://stackoverflow.com/questions/37934388/symbol-visibility-not-working-as-expected
after this patch, libwebsockets.a shows no symbols when checked like that and
the static-linked minimal examples only show -U for their other dynamic
imports.
In a handful of cases we use LWS_EXTERN on extern data declarations,
those then need to change to explicit extern.
lejp_parse() return type is an int... but in the function, the temp
for it is a char. This leads to badness that is currently worked
around by casting the return through a signed char type.
But that leads to more badness since if there's >127 bytes of buffer
left after the end of the JSON object, we misreport it.
Bite the bullet and fix the temp type, and fix up all the guys
who were working around it at the caller return casting to use the
resulting straight int.
If you are using this api, remove any casting you may have cut-
and-pasted like this
n = (int)(signed char)lejp_parse(...);
... to just be like this...
n = lejp_parse(...);
lejp-conf isn't the only user that needs to generate human-readable
JSON parsing error stacks.
Build it in with lejp and introduce an error code -> string api
