docs: specify Lua 5.1 dependencies and numeric version matching

Explain that LUA=TRUE uses FindLua51, while numeric LUA values use non-EXACT FindLua version matching. Name the Lua 5.1 development package required by the test build examples.

Validation: checked against accel-pppd/CMakeLists.txt and the installed FindLua51 module.
Signed-off-by: Denys Fedoryshchenko <denys.f@collabora.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/README.md b/README.md
index bac35421..80b0aeaa 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,9 @@ development libraries:
 
 * Net-SNMP for NETSNMP=TRUE
 * PostgreSQL client libraries for LOG_PGSQL_DEPRECATED=TRUE
-* Lua for LUA=TRUE or a specific Lua version such as LUA=5.3
+* Lua 5.1 development files for LUA=TRUE. A numeric value such as LUA=5.3
+  requests at least that Lua version through CMake's FindLua module; it does
+  not enforce an exact version.
 
 
 Building and installing