Compiler warnings

[csatt]

This probably should be classified as "cosmetic" instead of "bug", but one user has reported that his compile fails with 1.3.8 and 1.3.10 and succeeds with the fixes for this issue. The reason for that is not yet understood and no one else has reported such an issue. Most changes are to code that has existed since the original version of the sketch, and the others are in code added in version 1.3.2+ on 28-Jun, 2018, so this is not a recent breakage.

When the "Compiler warnings" option in the Arduino IDE Preferences is set to "All", several warnings are generated. These should be corrected:

/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:215:23: warning: left shift count >= width of type [-Wshift-count-overflow]
#define MAX_ULONG (1<<32)-1 // Max unsigned long integer
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:268:67: note: in definition of macro '_impl_CASSERT_LINE'
typedef char impl_PASTE(assertion_failed_on_line,line)[2*!!(predicate)-1];
^~~~~~~~~
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:272:1: note: in expansion of macro 'COMPILER_ASSERT'
COMPILER_ASSERT(MAX_IV_MEAS <= (unsigned long) MAX_ULONG);
^~~~~~~~~~~~~~~
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:272:48: note: in expansion of macro 'MAX_ULONG'
COMPILER_ASSERT(MAX_IV_MEAS <= (unsigned long) MAX_ULONG);
^~~~~~~~~
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino: In function 'void loop()':
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:475:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
(index < sizeof(adc_ch0_vals)) && !count_updated;
~~~~~~^~~~~~~~~
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:500:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
(index < sizeof(adc_ch0_vals)) && !voc_adc_found;
~~~~~~^~~~~~~~~
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino: In function 'void dump_eeprom()':
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1165:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
eeprom_addr < ((eeprom_valid_count + 2) * sizeof(float));
~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino: In function 'process_config_msg':
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1094:26: warning: 'config_val2' may be used uninitialized in this function [-Wmaybe-uninitialized]
eeprom_value = atof(config_val2);
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1001:9: note: 'config_val2' was declared here
char *config_val2;
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1122:40: warning: 'config_val' may be used uninitialized in this function [-Wmaybe-uninitialized]
set_second_relay_state((bool)atoi(config_val));
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1000:9: note: 'config_val' was declared here
char *config_val;
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1030:15: warning: 'config_type' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (strcmp_P(config_type, clk_div_str) == 0) {
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:999:9: note: 'config_type' was declared here
char *config_type;
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino: In function 'loop':
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1391:18: warning: 'round_up_mask' may be used uninitialized in this function [-Wmaybe-uninitialized]
sm_scale = (sm & round_up_mask) ? (sm >> shift_amt) + 1 : (sm >> shift_amt);
^
/Users/csatt/Documents/Arduino/IV_Swinger2/IV_Swinger2.ino:1367:15: note: 'round_up_mask' was declared here
int lg, sm, round_up_mask;
^