backtrace support compiled with more conditions
following #1356,
only enable backtrace compilation on linux+glibc.
Also, disable backtrace by default from "release" compilation,
so that less platforms get impacted by the new requirements.
Can be manually enabled/disabled using BACKTRACE=1/0.
diff --git a/programs/README.md b/programs/README.md
index 804cb8b..ca9056e 100644
--- a/programs/README.md
+++ b/programs/README.md
@@ -61,12 +61,12 @@
In which case, linking stage will fail if `lz4` library cannot be found.
This is useful to prevent silent feature disabling.
-- __ALL_SYMBOLS__ : `zstd` can display a stack backtrace if the execution
+- __BACKTRACE__ : `zstd` can display a stack backtrace when execution
generates a runtime exception. By default, this feature may be
degraded/disabled on some platforms unless additional compiler directives are
- applied. When triaging a runtime issue, enabling this feature can provided
+ applied. When triaging a runtime issue, enabling this feature can provide
more context to determine the location of the fault.
- Example : `make zstd ALL_SYMBOLS=1`
+ Example : `make zstd BACKTRACE=1`
#### Aggregation of parameters