[PROTON-1609] build C examples with c90 flag for older compilers

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: proton-c-0.17.0
• Fix Version/s: proton-c-0.18.0
• Component/s: examples
• Assignee: Alan Conway
• Reporter: Alan Conway
• Created: 03/Oct/17 21:14
• Updated: 24/Oct/17 08:44
• Resolved: 04/Oct/17 18:12

Description

The main proton library requires a c99 compiler (actually the overlap of c90 and c++03) but the examples should compile with c90 to ensure they work with older compiolers.

Fix CMakeLists to use the -std=c90 flag for examples with clang and gcc compilers, to get early warning of c90-incompatible code in the examples.